diff --git a/src/app/features/room/RoomTrainingLine.tsx b/src/app/features/room/RoomTrainingLine.tsx
new file mode 100644
index 00000000..147932de
--- /dev/null
+++ b/src/app/features/room/RoomTrainingLine.tsx
@@ -0,0 +1,25 @@
+import { Text, color, config } from 'folds';
+import { Room } from 'matrix-js-sdk';
+import React from 'react';
+import { useStateEvent } from '../../hooks/useStateEvent';
+import {
+  ROOM_NOTICE_EVENT_TYPE,
+  parseRoomNotice,
+  roomTrainingLine,
+} from '../../utils/trainingNotice';
+
+// The room's notice state event decides the line; no event, or a malformed one, no line. The
+// collector reads the version from the same event, so nothing is stored in the browser.
+export function RoomTrainingLine({ room }: { room: Room }) {
+  const event = useStateEvent(room, ROOM_NOTICE_EVENT_TYPE);
+  const line = roomTrainingLine(parseRoomNotice(event?.getContent()));
+  if (!line) return null;
+  return (
+    <Text
+      size="T200"
+      style={{ padding: `${config.space.S100} 0`, color: color.SurfaceVariant.OnContainer }}
+    >
+      {line}
+    </Text>
+  );
+}
diff --git a/src/app/features/room/RoomView.tsx b/src/app/features/room/RoomView.tsx
index a4f0d7af..3fbd81fa 100644
--- a/src/app/features/room/RoomView.tsx
+++ b/src/app/features/room/RoomView.tsx
@@ -13,6 +13,7 @@ import { RoomTimeline } from './RoomTimeline';
 import { RoomViewTyping } from './RoomViewTyping';
 import { RoomTombstone } from './RoomTombstone';
 import { RoomInput } from './RoomInput';
+import { RoomTrainingLine } from './RoomTrainingLine';
 import { RoomViewFollowing, RoomViewFollowingPlaceholder } from './RoomViewFollowing';
 import { Page } from '../../components/page';
 import { useKeyDown } from '../../hooks/useKeyDown';
@@ -104,6 +105,7 @@ export function RoomView({ eventId }: { eventId?: string }) {
       </Box>
       <Box shrink="No" direction="Column">
         <div style={{ padding: `0 ${config.space.S400}` }}>
+          <RoomTrainingLine room={room} />
           {tombstoneEvent ? (
             <RoomTombstone
               roomId={roomId}
diff --git a/src/app/pages/auth/TrainingNotice.tsx b/src/app/pages/auth/TrainingNotice.tsx
new file mode 100644
index 00000000..73b1caa0
--- /dev/null
+++ b/src/app/pages/auth/TrainingNotice.tsx
@@ -0,0 +1,41 @@
+import { Box, Checkbox, Text, color, config } from 'folds';
+import React from 'react';
+import { TRAINING_NOTICE_TEXT } from '../../utils/trainingNotice';
+
+type TrainingNoticeProps = {
+  checked: boolean;
+  onToggle: () => void;
+};
+
+// Registration only: ticking it is the newcomer's acceptance of the current notice version.
+export function TrainingNotice({ checked, onToggle }: TrainingNoticeProps) {
+  return (
+    <Box
+      direction="Column"
+      gap="200"
+      style={{
+        padding: config.space.S300,
+        borderRadius: config.radii.R300,
+        backgroundColor: color.SurfaceVariant.Container,
+        color: color.SurfaceVariant.OnContainer,
+        border: `${config.borderWidth.B300} solid ${color.SurfaceVariant.ContainerLine}`,
+      }}
+    >
+      <Text
+        as="label"
+        size="T300"
+        style={{ display: 'flex', alignItems: 'center', gap: config.space.S200 }}
+      >
+        <Checkbox
+          name="trainingAck"
+          size="300"
+          variant="Primary"
+          required
+          checked={checked}
+          onClick={onToggle}
+        />
+        {TRAINING_NOTICE_TEXT}
+      </Text>
+    </Box>
+  );
+}
diff --git a/src/app/pages/auth/register/PasswordRegisterForm.tsx b/src/app/pages/auth/register/PasswordRegisterForm.tsx
index c9b1924c..99feed1a 100644
--- a/src/app/pages/auth/register/PasswordRegisterForm.tsx
+++ b/src/app/pages/auth/register/PasswordRegisterForm.tsx
@@ -32,6 +32,7 @@ import { AsyncState, AsyncStatus, useAsyncCallback } from '../../../hooks/useAsy
 import { useAutoDiscoveryInfo } from '../../../hooks/useAutoDiscoveryInfo';
 import { RegisterError, RegisterResult, register, useRegisterComplete } from './registerUtil';
 import { FieldError } from '../FiledError';
+import { TrainingNotice } from '../TrainingNotice';
 import {
   AutoDummyStageDialog,
   AutoTermsStageDialog,
@@ -192,6 +193,7 @@ export function PasswordRegisterForm({
   const [formData, setFormData] = useState<FormData>();
 
   const [ongoingFlow, setOngoingFlow] = useState<UIAFlow>();
+  const [trainingAck, setTrainingAck] = useState(false);
 
   const [registerEmailState, registerEmail] = useRegisterEmail(mx);
 
@@ -389,7 +391,8 @@ export function PasswordRegisterForm({
           <FieldError message={registerError.data.error ?? 'Failed to register. Unknown Reason.'} />
         )}
         <span data-spacing-node />
-        <Button variant="Primary" size="500" type="submit">
+        <TrainingNotice checked={trainingAck} onToggle={() => setTrainingAck((ack) => !ack)} />
+        <Button variant="Primary" size="500" type="submit" disabled={!trainingAck}>
           <Text as="span" size="B500">
             Register
           </Text>
diff --git a/src/app/utils/trainingNotice.test.ts b/src/app/utils/trainingNotice.test.ts
new file mode 100644
index 00000000..0663d2f9
--- /dev/null
+++ b/src/app/utils/trainingNotice.test.ts
@@ -0,0 +1,68 @@
+import { describe, expect, it } from 'vitest';
+import {
+  MAX_NOTICE_VERSION,
+  ROOM_NOTICE_EVENT_TYPE,
+  TRAINING_NOTICE_TEXT,
+  parseRoomNotice,
+  roomTrainingLine,
+} from './trainingNotice';
+
+const lineFor = (content: unknown) => roomTrainingLine(parseRoomNotice(content));
+
+describe('training notice', () => {
+  it('says exactly the ruled sentence and never mentions Discord', () => {
+    expect(TRAINING_NOTICE_TEXT).toBe(
+      "Everything said here may be used to train GameCult's AI stewards."
+    );
+    expect(TRAINING_NOTICE_TEXT.toLowerCase()).not.toContain('discord');
+  });
+
+  it('reads the notice from the org.gamecult.notice state event', () => {
+    expect(ROOM_NOTICE_EVENT_TYPE).toBe('org.gamecult.notice');
+  });
+
+  it('shows the train line only where the room declares train', () => {
+    expect(parseRoomNotice({ version: 2, scope: 'train' })).toEqual({ version: 2, scope: 'train' });
+    expect(lineFor({ version: 2, scope: 'train' })).toBe(TRAINING_NOTICE_TEXT);
+    expect(lineFor({ version: 1, scope: 'study' })).toBeUndefined();
+    expect(lineFor({ version: 1, scope: 'show' })).toBeUndefined();
+  });
+
+  it('shows nothing where the notice is absent', () => {
+    expect(lineFor(undefined)).toBeUndefined();
+    expect(lineFor(null)).toBeUndefined();
+    expect(lineFor({})).toBeUndefined();
+  });
+
+  it('shows nothing where the notice is malformed in any way', () => {
+    expect(lineFor('train')).toBeUndefined();
+    expect(lineFor({ scope: 'train' })).toBeUndefined();
+    expect(lineFor({ version: 1 })).toBeUndefined();
+    expect(lineFor({ version: 0, scope: 'train' })).toBeUndefined();
+    expect(lineFor({ version: -1, scope: 'train' })).toBeUndefined();
+    expect(lineFor({ version: 1.5, scope: 'train' })).toBeUndefined();
+    expect(lineFor({ version: '1', scope: 'train' })).toBeUndefined();
+    expect(lineFor({ version: null, scope: 'train' })).toBeUndefined();
+  });
+
+  it('rejects a version written with leading zeros', () => {
+    expect(lineFor({ version: '01', scope: 'train' })).toBeUndefined();
+    expect(lineFor({ version: '007', scope: 'train' })).toBeUndefined();
+  });
+
+  it('bounds the version at 4294967295', () => {
+    expect(MAX_NOTICE_VERSION).toBe(4294967295);
+    expect(lineFor({ version: 4294967295, scope: 'train' })).toBe(TRAINING_NOTICE_TEXT);
+    expect(parseRoomNotice({ version: 4294967295, scope: 'train' })?.version).toBe(4294967295);
+    expect(lineFor({ version: 4294967296, scope: 'train' })).toBeUndefined();
+    expect(lineFor({ version: Number.MAX_SAFE_INTEGER, scope: 'train' })).toBeUndefined();
+    expect(lineFor({ version: 4294967295.5, scope: 'train' })).toBeUndefined();
+    expect(lineFor({ version: '4294967295', scope: 'train' })).toBeUndefined();
+  });
+
+  it('rejects an unknown or wrongly cased scope', () => {
+    expect(lineFor({ version: 1, scope: 'everything' })).toBeUndefined();
+    expect(lineFor({ version: 1, scope: 'Train' })).toBeUndefined();
+    expect(lineFor({ version: 1, scope: ['train'] })).toBeUndefined();
+  });
+});
diff --git a/src/app/utils/trainingNotice.ts b/src/app/utils/trainingNotice.ts
new file mode 100644
index 00000000..7f60cce4
--- /dev/null
+++ b/src/app/utils/trainingNotice.ts
@@ -0,0 +1,35 @@
+import { StateEvent } from '../../types/matrix/room';
+
+export const TRAINING_NOTICE_TEXT =
+  "Everything said here may be used to train GameCult's AI stewards.";
+
+/**
+ * Heimdall's ruling: a room's notice is a room state event, not a pinned message. Type below,
+ * state_key '', content `{version, scope}`; scope exactly one of show, study or train. Heimdall's
+ * one version rule: a positive integer, no leading zeros, no greater than 4294967295; anything
+ * else is malformed. Absent or malformed in any way means no train line.
+ */
+export const MAX_NOTICE_VERSION = 4294967295;
+export const ROOM_NOTICE_EVENT_TYPE = StateEvent.GameCultNotice;
+
+export type RoomNotice = { version: number; scope: 'show' | 'study' | 'train' };
+
+/** The notice a state event's content declares, or undefined: no scope is ever inferred. */
+export const parseRoomNotice = (content: unknown): RoomNotice | undefined => {
+  if (typeof content !== 'object' || content === null) return undefined;
+  const { version, scope } = content as { version?: unknown; scope?: unknown };
+  if (
+    typeof version === 'number' &&
+    Number.isSafeInteger(version) &&
+    version > 0 &&
+    version <= MAX_NOTICE_VERSION &&
+    (scope === 'show' || scope === 'study' || scope === 'train')
+  ) {
+    return { version, scope };
+  }
+  return undefined;
+};
+
+/** The line a room shows: only a notice that says `train` in terms gets the train sentence. */
+export const roomTrainingLine = (notice: RoomNotice | undefined): string | undefined =>
+  notice?.scope === 'train' ? TRAINING_NOTICE_TEXT : undefined;
diff --git a/src/types/matrix/room.ts b/src/types/matrix/room.ts
index c73c0f0b..8d6b89dd 100644
--- a/src/types/matrix/room.ts
+++ b/src/types/matrix/room.ts
@@ -23,6 +23,7 @@ export enum StateEvent {
   RoomMember = 'm.room.member',
   RoomThirdPartyInvite = 'm.room.third_party_invite',
   RoomPowerLevels = 'm.room.power_levels',
+  GameCultNotice = 'org.gamecult.notice',
   RoomName = 'm.room.name',
   RoomTopic = 'm.room.topic',
   RoomAvatar = 'm.room.avatar',