diff --git a/backend/migrations/1787000000000_add-customer-disabled-at.js b/backend/migrations/1787000000000_add-customer-disabled-at.js
new file mode 100644
index 0000000..0abb90f
--- /dev/null
+++ b/backend/migrations/1787000000000_add-customer-disabled-at.js
@@ -0,0 +1,19 @@
+exports.up = (pgm) => {
+  pgm.sql(`
+    -- Nullable timestamp rather than a boolean: disabling is reversible, and
+    -- this records when it happened without a second column.
+    ALTER TABLE customers ADD COLUMN IF NOT EXISTS disabled_at TIMESTAMPTZ;
+
+    -- attachCustomer joins customers on every authenticated request to check
+    -- this, so the lookup wants an index on the active case.
+    CREATE INDEX IF NOT EXISTS customers_disabled_at_idx
+      ON customers (disabled_at) WHERE disabled_at IS NOT NULL;
+  `);
+};
+
+exports.down = (pgm) => {
+  pgm.sql(`
+    DROP INDEX IF EXISTS customers_disabled_at_idx;
+    ALTER TABLE customers DROP COLUMN IF EXISTS disabled_at;
+  `);
+};
diff --git a/backend/src/middleware/customerAuth.ts b/backend/src/middleware/customerAuth.ts
index bf0c5b5..a27f3e2 100755
--- a/backend/src/middleware/customerAuth.ts
+++ b/backend/src/middleware/customerAuth.ts
@@ -12,8 +12,15 @@ declare global {
 export async function attachCustomer(req: Request, _res: Response, next: NextFunction): Promise<void> {
   const token = req.cookies?.rd_session;
   if (!token) return next();
+  // Joined to customers so a disabled account stops resolving at once, rather
+  // than when its 30-day cookie eventually expires. Register, login and
+  // password reset all mint sessions, so checking here covers every path
+  // instead of three separate ones.
   const { rows } = await pool.query(
-    `SELECT customer_id FROM customer_sessions WHERE token = $1 AND expires_at > now()`,
+    `SELECT s.customer_id
+     FROM customer_sessions s
+     JOIN customers c ON c.id = s.customer_id
+     WHERE s.token = $1 AND s.expires_at > now() AND c.disabled_at IS NULL`,
     [token]
   );
   if (rows.length) req.customerId = rows[0].customer_id;
diff --git a/backend/src/routes/adminCustomers.ts b/backend/src/routes/adminCustomers.ts
index b84c1c0..81753da 100755
--- a/backend/src/routes/adminCustomers.ts
+++ b/backend/src/routes/adminCustomers.ts
@@ -7,7 +7,7 @@ const router = Router();
 router.get('/', asyncRoute(async (_req: Request, res: Response) => {
   const { rows } = await pool.query(`
     SELECT
-      c.id, c.email, c.name, c.email_verified, c.marketing_consent, c.created_at,
+      c.id, c.email, c.name, c.email_verified, c.marketing_consent, c.created_at, c.disabled_at,
       COUNT(o.id) FILTER (WHERE o.status = 'completed') AS order_count,
       COALESCE(SUM(o.amount_cents) FILTER (WHERE o.status = 'completed'), 0) AS total_spent_cents,
       MAX(o.created_at) AS last_order_at,
@@ -27,6 +27,71 @@ router.get('/', asyncRoute(async (_req: Request, res: Response) => {
   res.json(rows);
 }));
 
+// Disabling is reversible, so this records a timestamp rather than flipping a
+// boolean — when it happened comes free.
+//
+// Everything below happens in one transaction. A disable that evicted the
+// sessions but left the cart held, or vice versa, would be worse than either
+// outcome alone.
+router.post('/:id/disable', asyncRoute(async (req: Request, res: Response) => {
+  const client = await pool.connect();
+  try {
+    await client.query('BEGIN');
+
+    const { rows } = await client.query(
+      `UPDATE customers SET disabled_at = now() WHERE id = $1 RETURNING id`,
+      [req.params.id]
+    );
+    if (!rows.length) {
+      await client.query('ROLLBACK');
+      return res.status(404).json({ error: 'not found' });
+    }
+
+    // Immediate eviction. attachCustomer also refuses a disabled account, so
+    // this is belt and braces — but it means the rows are gone rather than
+    // lingering until their 30-day expiry.
+    await client.query(`DELETE FROM customer_sessions WHERE customer_id = $1`, [req.params.id]);
+
+    // A disabled account cannot check out, so holding one-of-a-kind stock off
+    // the storefront until the expiry sweep serves nobody. Guarded on
+    // 'reserved' so a sold item is never resurrected.
+    const { rows: held } = await client.query(
+      `DELETE FROM cart_items ci
+       USING carts ca
+       WHERE ci.cart_id = ca.id AND ca.customer_id = $1
+       RETURNING ci.item_id`,
+      [req.params.id]
+    );
+    if (held.length) {
+      await client.query(
+        `UPDATE items SET status = 'available', reserved_until = NULL
+         WHERE id = ANY($1::int[]) AND status = 'reserved'`,
+        [held.map((row: { item_id: number }) => row.item_id)]
+      );
+    }
+
+    await client.query('COMMIT');
+    res.status(204).end();
+  } catch (err) {
+    await client.query('ROLLBACK');
+    throw err;
+  } finally {
+    client.release();
+  }
+}));
+
+// Restores sign-in only. Items released by the disable stay released — they may
+// well have been sold to someone else in the meantime, and silently re-reserving
+// them would be worse than making the customer add them again.
+router.post('/:id/enable', asyncRoute(async (req: Request, res: Response) => {
+  const { rows } = await pool.query(
+    `UPDATE customers SET disabled_at = NULL WHERE id = $1 RETURNING id`,
+    [req.params.id]
+  );
+  if (!rows.length) return res.status(404).json({ error: 'not found' });
+  res.status(204).end();
+}));
+
 router.get('/:id/reserved', asyncRoute(async (req: Request, res: Response) => {
   const { rows } = await pool.query(
     `SELECT i.id AS item_id, i.name, i.price_cents, ci.added_at, ci.expires_at
diff --git a/backend/src/routes/customers.ts b/backend/src/routes/customers.ts
index 5e33b12..90f2e39 100755
--- a/backend/src/routes/customers.ts
+++ b/backend/src/routes/customers.ts
@@ -111,7 +111,7 @@ router.post('/request-password-reset', passwordResetRequestLimiter, asyncRoute(a
   const { rows } = await pool.query(`SELECT * FROM customers WHERE email = $1`, [email]);
   const customer = rows[0];
 
-  if (customer) {
+  if (customer && !customer.disabled_at) {
     // Supersede any outstanding token, so a link cannot be resurrected later
     // from an older message in the customer's inbox.
     await pool.query(`DELETE FROM customer_tokens WHERE customer_id = $1 AND kind = 'password_reset'`, [customer.id]);
@@ -156,6 +156,13 @@ router.post('/reset-password', asyncRoute(async (req: Request, res: Response) =>
   if (!rows.length) return res.status(400).json({ error: 'invalid or expired token' });
   const customerId = rows[0].customer_id;
 
+  // A token issued before the account was disabled would otherwise still mint a
+  // fresh session.
+  const { rows: owner } = await pool.query(`SELECT disabled_at FROM customers WHERE id = $1`, [customerId]);
+  if (owner[0]?.disabled_at) {
+    return res.status(403).json({ error: 'this account has been disabled' });
+  }
+
   const passwordHash = await bcrypt.hash(String(password), 12);
 
   const client = await pool.connect();
@@ -194,6 +201,11 @@ router.post('/login', async (req: Request, res: Response) => {
   if (!customer || !(await bcrypt.compare(password || '', customer.password_hash))) {
     return res.status(401).json({ error: 'invalid email or password' });
   }
+  // Only after the password checks out, so a wrong password still looks like a
+  // wrong password and this does not become a bulk membership oracle.
+  if (customer.disabled_at) {
+    return res.status(403).json({ error: 'this account has been disabled' });
+  }
   const sessionToken = await createSession(customer.id);
   setSessionCookie(res, sessionToken);
   res.json(publicCustomer(customer));
diff --git a/backend/tests/integration/disableCustomer.integration.test.ts b/backend/tests/integration/disableCustomer.integration.test.ts
new file mode 100644
index 0000000..1ebb958
--- /dev/null
+++ b/backend/tests/integration/disableCustomer.integration.test.ts
@@ -0,0 +1,205 @@
+import request from 'supertest';
+import app from '../../src/app';
+import { pool } from '../../src/db';
+import { resetDb, closeDb } from './setup/testDb';
+
+beforeEach(async () => {
+  await resetDb();
+});
+
+afterAll(async () => {
+  await pool.end();
+  await closeDb();
+});
+
+const PASSWORD = 'supersecret123';
+
+async function register(email: string) {
+  const agent = request.agent(app);
+  const res = await agent.post('/api/customers/register').send({ email, password: PASSWORD });
+  expect(res.status).toBe(200);
+  const { rows } = await pool.query(`SELECT id FROM customers WHERE email = $1`, [email]);
+  return { agent, id: rows[0].id as number };
+}
+
+async function createItem(name: string) {
+  const { rows } = await pool.query(
+    `INSERT INTO items (name, price_cents) VALUES ($1, 1000) RETURNING id`,
+    [name]
+  );
+  return rows[0].id as number;
+}
+
+describe('disabling a customer', () => {
+  it('is reported in the admin customer list', async () => {
+    const { id } = await register('flag@example.com');
+
+    await request(app).post(`/api/admin/customers/${id}/disable`).expect(204);
+
+    const res = await request(app).get('/api/admin/customers');
+    const customer = res.body.find((c: { id: number }) => c.id === id);
+    expect(customer.disabled_at).toBeTruthy();
+  });
+
+  it('refuses the sign-in with an explicit reason, not a credential failure', async () => {
+    const { id } = await register('told@example.com');
+    await request(app).post(`/api/admin/customers/${id}/disable`).expect(204);
+
+    const res = await request(app)
+      .post('/api/customers/login')
+      .send({ email: 'told@example.com', password: PASSWORD });
+
+    // A generic 401 would send them round the password-reset loop forever.
+    expect(res.status).toBe(403);
+    expect(res.body.error).toMatch(/disabled/i);
+  });
+
+  it('still refuses a sign-in with the wrong password, without revealing the disable', async () => {
+    const { id } = await register('wrongpw@example.com');
+    await request(app).post(`/api/admin/customers/${id}/disable`).expect(204);
+
+    const res = await request(app)
+      .post('/api/customers/login')
+      .send({ email: 'wrongpw@example.com', password: 'not-the-password' });
+    expect(res.status).toBe(401);
+  });
+
+  it('kills sessions that already existed', async () => {
+    const { agent, id } = await register('evicted@example.com');
+    expect((await agent.get('/api/customers/me')).status).toBe(200);
+
+    await request(app).post(`/api/admin/customers/${id}/disable`).expect(204);
+
+    // The cookie is still held by the agent; it must stop working immediately
+    // rather than at its 30-day expiry.
+    expect((await agent.get('/api/customers/me')).status).toBe(401);
+  });
+
+  it('releases items the customer was holding', async () => {
+    const itemId = await createItem('Held item');
+    const { agent, id } = await register('holder@example.com');
+    expect((await agent.post(`/api/cart/items/${itemId}`)).status).toBe(201);
+
+    await request(app).post(`/api/admin/customers/${id}/disable`).expect(204);
+
+    const item = await request(app).get(`/api/items/${itemId}`);
+    expect(item.body.status).toBe('available');
+
+    const { rows } = await pool.query(`SELECT COUNT(*)::int AS n FROM cart_items WHERE item_id = $1`, [itemId]);
+    expect(rows[0].n).toBe(0);
+  });
+
+  it('leaves a released item purchasable by someone else', async () => {
+    const itemId = await createItem('Freed item');
+    const { agent: first, id } = await register('first@example.com');
+    await first.post(`/api/cart/items/${itemId}`);
+    await request(app).post(`/api/admin/customers/${id}/disable`).expect(204);
+
+    const { agent: second } = await register('second@example.com');
+    expect((await second.post(`/api/cart/items/${itemId}`)).status).toBe(201);
+  });
+
+  it('does not resurrect an item that was already sold', async () => {
+    const itemId = await createItem('Sold item');
+    const { agent, id } = await register('sold@example.com');
+    await agent.post(`/api/cart/items/${itemId}`);
+    await pool.query(`UPDATE items SET status = 'sold' WHERE id = $1`, [itemId]);
+
+    await request(app).post(`/api/admin/customers/${id}/disable`).expect(204);
+
+    const { rows } = await pool.query(`SELECT status FROM items WHERE id = $1`, [itemId]);
+    expect(rows[0].status).toBe('sold');
+  });
+
+  it('blocks the self-service data export and account deletion', async () => {
+    const { agent, id } = await register('gdpr@example.com');
+    await request(app).post(`/api/admin/customers/${id}/disable`).expect(204);
+
+    expect((await agent.get('/api/customers/me/export')).status).toBe(401);
+    expect((await agent.delete('/api/customers/me')).status).toBe(401);
+  });
+
+  it('sends no reset mail and issues no token for a disabled account', async () => {
+    const { id } = await register('noreset@example.com');
+    await request(app).post(`/api/admin/customers/${id}/disable`).expect(204);
+
+    // Still 200, so the endpoint stays non-enumerating.
+    const res = await request(app)
+      .post('/api/customers/request-password-reset')
+      .send({ email: 'noreset@example.com' });
+    expect(res.status).toBe(200);
+
+    const { rows } = await pool.query(
+      `SELECT COUNT(*)::int AS n FROM customer_tokens WHERE customer_id = $1 AND kind = 'password_reset'`,
+      [id]
+    );
+    expect(rows[0].n).toBe(0);
+  });
+
+  it('refuses to complete a reset whose token predates the disable', async () => {
+    const { id } = await register('midreset@example.com');
+    await request(app).post('/api/customers/request-password-reset').send({ email: 'midreset@example.com' });
+    const { rows } = await pool.query(
+      `SELECT token FROM customer_tokens WHERE customer_id = $1 AND kind = 'password_reset'`,
+      [id]
+    );
+    const token = rows[0].token;
+
+    await request(app).post(`/api/admin/customers/${id}/disable`).expect(204);
+
+    const res = await request(app)
+      .post('/api/customers/reset-password')
+      .send({ token, password: 'a-brand-new-password' });
+    expect(res.status).toBe(403);
+  });
+
+  it('rejects registering again with the same address', async () => {
+    const { id } = await register('reregister@example.com');
+    await request(app).post(`/api/admin/customers/${id}/disable`).expect(204);
+
+    // Otherwise disabling is trivially undone by signing up again.
+    const res = await request(app)
+      .post('/api/customers/register')
+      .send({ email: 'reregister@example.com', password: PASSWORD });
+    expect(res.status).toBe(409);
+  });
+});
+
+describe('re-enabling a customer', () => {
+  it('restores sign-in', async () => {
+    const { id } = await register('back@example.com');
+    await request(app).post(`/api/admin/customers/${id}/disable`).expect(204);
+    await request(app).post(`/api/admin/customers/${id}/enable`).expect(204);
+
+    const res = await request(app)
+      .post('/api/customers/login')
+      .send({ email: 'back@example.com', password: PASSWORD });
+    expect(res.status).toBe(200);
+  });
+
+  it('clears the disabled timestamp', async () => {
+    const { id } = await register('cleared@example.com');
+    await request(app).post(`/api/admin/customers/${id}/disable`).expect(204);
+    await request(app).post(`/api/admin/customers/${id}/enable`).expect(204);
+
+    const res = await request(app).get('/api/admin/customers');
+    const customer = res.body.find((c: { id: number }) => c.id === id);
+    expect(customer.disabled_at).toBeNull();
+  });
+
+  it('does not give back the items that were released', async () => {
+    const itemId = await createItem('Not returned');
+    const { agent, id } = await register('norestore@example.com');
+    await agent.post(`/api/cart/items/${itemId}`);
+    await request(app).post(`/api/admin/customers/${id}/disable`).expect(204);
+    await request(app).post(`/api/admin/customers/${id}/enable`).expect(204);
+
+    const item = await request(app).get(`/api/items/${itemId}`);
+    expect(item.body.status).toBe('available');
+  });
+
+  it('returns 404 for a customer that does not exist', async () => {
+    expect((await request(app).post('/api/admin/customers/999999/disable')).status).toBe(404);
+    expect((await request(app).post('/api/admin/customers/999999/enable')).status).toBe(404);
+  });
+});
diff --git a/frontend/src/admin/Admin.tsx b/frontend/src/admin/Admin.tsx
index 4f3ce63..3ad2902 100755
--- a/frontend/src/admin/Admin.tsx
+++ b/frontend/src/admin/Admin.tsx
@@ -1,4 +1,4 @@
-import { useEffect, useState } from 'react';
+import { useEffect, useRef, useState } from 'react';
 import {
   Layout, Table, Button, Form, Input, InputNumber, Upload, Modal,
   Space, Tag, Typography, Switch, message, Image as AntImage, theme, Tabs,
@@ -39,7 +39,16 @@ function Inventory() {
   const [filters, setFilters] = useState<ItemFilters>(EMPTY_FILTERS);
   const { mode } = useThemeMode();
 
-  const load = (active: ItemFilters = filters) => fetchAdminItems(active).then(setItems);
+  // Typing in the price fields fires a request per keystroke, so responses can
+  // arrive out of order and an older one can repaint stale rows over a newer
+  // result. Only the most recently issued request is allowed to set state.
+  const latestRequest = useRef(0);
+  const load = (active: ItemFilters = filters) => {
+    const seq = ++latestRequest.current;
+    return fetchAdminItems(active).then(rows => {
+      if (seq === latestRequest.current) setItems(rows);
+    });
+  };
 
   // The item form needs the current category tree and tag list; both change
   // from the sibling tabs, so they're refetched whenever the modal opens.
diff --git a/frontend/src/admin/Customers.tsx b/frontend/src/admin/Customers.tsx
index 1a3fece..7c430e1 100755
--- a/frontend/src/admin/Customers.tsx
+++ b/frontend/src/admin/Customers.tsx
@@ -3,6 +3,7 @@ import { Table, Drawer, Descriptions, Tag, Typography, Spin, Empty, Modal, Butto
 import type { ColumnsType } from 'antd/es/table';
 import {
   fetchCustomers, fetchCustomerDetail, fetchReservedItems, releaseReservedItem,
+  setCustomerDisabled,
   CustomerSummary, CustomerDetail, ReservedItem
 } from './adminCustomersApi';
 
@@ -18,6 +19,7 @@ export default function Customers() {
   const [reserved, setReserved] = useState<ReservedItem[]>([]);
   const [reservedLoading, setReservedLoading] = useState(false);
   const [releasing, setReleasing] = useState<number | null>(null);
+  const [togglingId, setTogglingId] = useState<number | null>(null);
 
   function load() {
     return fetchCustomers().then(rows => { setCustomers(rows); setLoading(false); });
@@ -46,6 +48,46 @@ export default function Customers() {
     }
   }
 
+  function handleToggleDisabled(customer: CustomerSummary) {
+    const disabling = !customer.disabled_at;
+
+    Modal.confirm({
+      title: disabling ? `Disable ${customer.email}?` : `Re-enable ${customer.email}?`,
+      content: disabling ? (
+        <span>
+          They will be signed out everywhere immediately and told the account is disabled if they
+          try to sign in.
+          {customer.reserved_count > 0 && (
+            <> Their {customer.reserved_count} reserved item
+              {customer.reserved_count === 1 ? '' : 's'} will be released back to the storefront.</>
+          )}
+          {' '}Self-service data export and account deletion stop working too, so any such request
+          has to be handled by hand.
+        </span>
+      ) : (
+        <span>
+          They will be able to sign in again. Items released when the account was disabled are not
+          returned — those may already have sold.
+        </span>
+      ),
+      okText: disabling ? 'Disable' : 'Re-enable',
+      okButtonProps: { danger: disabling },
+      onOk: async () => {
+        setTogglingId(customer.id);
+        try {
+          await setCustomerDisabled(customer.id, disabling);
+        } catch (err) {
+          message.error(`Couldn't ${disabling ? 'disable' : 're-enable'} — ${(err as Error).message}`);
+          return;
+        } finally {
+          setTogglingId(null);
+        }
+        message.success(disabling ? 'Account disabled' : 'Account re-enabled');
+        load();
+      }
+    });
+  }
+
   async function handleRelease(item: ReservedItem) {
     if (!reservedFor) return;
     setReleasing(item.item_id);
@@ -90,6 +132,14 @@ export default function Customers() {
       onFilter: (value, row) => row.marketing_consent === value,
       render: (v: boolean) => <Tag color={v ? 'blue' : 'default'}>{v ? 'Yes' : 'No'}</Tag>
     },
+    {
+      title: 'Status',
+      dataIndex: 'disabled_at',
+      render: (disabledAt: string | null) =>
+        disabledAt
+          ? <Tag color="red">DISABLED</Tag>
+          : <Tag color="green">ACTIVE</Tag>
+    },
     {
       title: 'Reserved',
       dataIndex: 'reserved_count',
@@ -127,6 +177,21 @@ export default function Customers() {
       sorter: (a, b) => new Date(a.last_order_at || 0).getTime() - new Date(b.last_order_at || 0).getTime(),
       render: (v: string | null) => (v ? new Date(v).toLocaleDateString() : '—')
     },
+    {
+      title: '',
+      key: 'actions',
+      render: (_: unknown, customer: CustomerSummary) => (
+        <Button
+          size="small"
+          danger={!customer.disabled_at}
+          loading={togglingId === customer.id}
+          // The row opens the detail drawer, so this must not bubble.
+          onClick={(event) => { event.stopPropagation(); handleToggleDisabled(customer); }}
+        >
+          {customer.disabled_at ? 'Re-enable' : 'Disable'}
+        </Button>
+      )
+    },
     {
       title: 'Joined',
       dataIndex: 'created_at',
diff --git a/frontend/src/admin/adminCustomersApi.ts b/frontend/src/admin/adminCustomersApi.ts
index fa3a451..0bf45dd 100755
--- a/frontend/src/admin/adminCustomersApi.ts
+++ b/frontend/src/admin/adminCustomersApi.ts
@@ -9,6 +9,7 @@ export interface CustomerSummary {
   total_spent_cents: number;
   last_order_at: string | null;
   reserved_count: number;
+  disabled_at: string | null;
 }
 
 export interface ReservedItem {
@@ -69,3 +70,15 @@ export async function releaseReservedItem(customerId: number, itemId: number): P
     throw new Error(detail.error || 'failed to release item');
   }
 }
+
+export async function setCustomerDisabled(customerId: number, disabled: boolean): Promise<void> {
+  const res = await fetch(`/api/admin/customers/${customerId}/${disabled ? 'disable' : 'enable'}`, {
+    method: 'POST'
+  });
+  // Reporting success for a disable that failed would leave an account the
+  // admin believes is locked still fully usable.
+  if (!res.ok) {
+    const detail = await res.json().catch(() => ({}));
+    throw new Error(detail.error || `failed to ${disabled ? 'disable' : 'enable'} account`);
+  }
+}
diff --git a/frontend/tests/e2e/admin-disable-customer.spec.ts b/frontend/tests/e2e/admin-disable-customer.spec.ts
new file mode 100644
index 0000000..d5abde5
--- /dev/null
+++ b/frontend/tests/e2e/admin-disable-customer.spec.ts
@@ -0,0 +1,107 @@
+import { test, expect, Page } from '@playwright/test';
+
+const PASSWORD = 'supersecret123';
+const uniqueEmail = () => `disable-${Date.now().toString(36)}${Math.random().toString(36).slice(2, 7)}@example.com`;
+
+async function register(page: Page, email: string) {
+  await page.goto('/register');
+  await page.getByRole('textbox', { name: 'Email' }).fill(email);
+  await page.getByLabel('Password').fill(PASSWORD);
+  await page.getByRole('button', { name: 'Create account' }).click();
+  await expect(page).toHaveURL(/\/account/);
+}
+
+async function customerRow(page: Page, email: string) {
+  await page.goto('/admin');
+  await page.getByRole('tab', { name: 'Customers' }).click();
+  const row = page.getByRole('row').filter({ hasText: email });
+  await expect(row).toBeVisible();
+  return row;
+}
+
+test.describe('Disabling a customer account', () => {
+  test('an admin can disable an account and the customer is told at sign-in', async ({ page }) => {
+    const email = uniqueEmail();
+    await register(page, email);
+
+    const row = await customerRow(page, email);
+    await expect(row.getByText('ACTIVE')).toBeVisible();
+
+    await row.getByRole('button', { name: 'Disable' }).click();
+    await page.getByRole('dialog').getByRole('button', { name: 'Disable' }).click();
+    await expect(page.getByText('Account disabled')).toBeVisible();
+
+    const updated = page.getByRole('row').filter({ hasText: email });
+    await expect(updated.getByText('DISABLED')).toBeVisible();
+
+    // A generic credential error would send a real customer round the
+    // password-reset loop forever.
+    await page.goto('/login');
+    await page.getByRole('textbox', { name: 'Email' }).fill(email);
+    await page.getByLabel('Password').fill(PASSWORD);
+    await page.getByRole('button', { name: 'Log in' }).click();
+    await expect(page.getByText(/disabled/i)).toBeVisible();
+  });
+
+  test('an existing session stops working immediately', async ({ page, request }) => {
+    const email = uniqueEmail();
+    await register(page, email);
+
+    // Still signed in from registration, in this same browser context.
+    await page.goto('/account');
+    await expect(page.getByText(email)).toBeVisible();
+
+    const customers = await (await request.get('/api/admin/customers')).json();
+    const id = customers.find((c: { email: string }) => c.email === email).id;
+    await request.post(`/api/admin/customers/${id}/disable`);
+
+    // The cookie is unchanged, so this proves the server rejects it rather
+    // than the browser having discarded it.
+    await page.goto('/account');
+    await expect(page).toHaveURL(/\/login/);
+  });
+
+  test('re-enabling restores sign-in', async ({ page, request }) => {
+    const email = uniqueEmail();
+    await register(page, email);
+
+    const customers = await (await request.get('/api/admin/customers')).json();
+    const id = customers.find((c: { email: string }) => c.email === email).id;
+    await request.post(`/api/admin/customers/${id}/disable`);
+
+    const row = await customerRow(page, email);
+    await row.getByRole('button', { name: 'Re-enable' }).click();
+    await page.getByRole('dialog').getByRole('button', { name: 'Re-enable' }).click();
+    await expect(page.getByText('Account re-enabled')).toBeVisible();
+
+    await page.goto('/login');
+    await page.getByRole('textbox', { name: 'Email' }).fill(email);
+    await page.getByLabel('Password').fill(PASSWORD);
+    await page.getByRole('button', { name: 'Log in' }).click();
+    await expect(page).toHaveURL(/\/account/);
+  });
+
+  test('the confirmation warns that held items will be released', async ({ page, request }) => {
+    const email = uniqueEmail();
+    const itemName = `Held ${Date.now().toString(36)}`;
+
+    const created = await request.post('/api/admin/items', {
+      multipart: { name: itemName, description: '', price: '40', category_id: '', tags: '[]' }
+    });
+    const itemId = (await created.json()).id as number;
+
+    await register(page, email);
+    expect((await page.request.post(`/api/cart/items/${itemId}`)).status()).toBe(201);
+
+    const row = await customerRow(page, email);
+    await row.getByRole('button', { name: 'Disable' }).click();
+
+    // The consequence has to be visible at the moment of the decision.
+    await expect(page.getByText(/1 reserved item/)).toBeVisible();
+    await page.getByRole('dialog').getByRole('button', { name: 'Disable' }).click();
+    await expect(page.getByText('Account disabled')).toBeVisible();
+
+    const item = await (await request.get(`/api/items/${itemId}`)).json();
+    expect(item.status).toBe('available');
+  });
+});