Mail notifications have a short disclaimer:
There will be no other notifications in case of further activity unless
you visit this page while logged in. [...]
However, the links in the notification do not ensure that a logout or a login under a different username is noticed by a reasonably attentive user.
I would like to see the links:
https://en.wikipedia.org/w/index.php?title=Page_title&diff=0&oldid=4711
changed to:
https://en.wikipedia.org/w/index.php?title=Page_title&diff=0&oldid=4711&requser=Username
adding a parameter "requser" to index.php.
The semantics would be that if "requser" is set and there is no user logged in or its username is different to the value of "requser", the page would link/redirect to a Special:UserLogin (&returnto=...&returntoquery=...) instead with a banner: "The link you followed suggested that you should be logged in as 'Username', for example to keep your watchlist up to date. You can either log in now or view the requested page (logged out|under your current log in)."