Add tip related to user destinations in STOMP

See gh-26986

src/docs/asciidoc/web/websocket.adoc

@@ -1818,12 +1818,16 @@ its own implementation of `WebSocketMessageBrokerConfigurer` that is marked with
 An application can send messages that target a specific user, and Spring's STOMP support
 recognizes destinations prefixed with `/user/` for this purpose.
 For example, a client might subscribe to the `/user/queue/position-updates` destination.
-This destination is handled by the `UserDestinationMessageHandler` and
+`UserDestinationMessageHandler` handles this destination and transforms it into a
-transformed into a destination unique to the user session
+destination unique to the user session (such as `/queue/position-updates-user123`).
-(such as `/queue/position-updates-user123`). This provides the convenience of subscribing
+This provides the convenience of subscribing to a generically named destination while,
-to a generically named destination while, at the same time, ensuring no collisions
+at the same time, ensuring no collisions with other users who subscribe to the same
-with other users who subscribe to the same destination so that each user can receive
+destination so that each user can receive unique stock position updates.
-unique stock position updates.
+
+TIP: When working with user destinations, it is important to configure broker and
+application destination prefixes as shown in <<websocket-stomp-enable>>, or otherwise the
+broker would handle "/user" prefixed messages that should only be handled by
+`UserDestinationMessageHandler`.
 
 On the sending side, messages can be sent to a destination such as
 pass:q[`/user/{username}/queue/position-updates`], which in turn is translated