People returning to a page they have been to before but no longer have access because they are no longer logged in are given an opportunity to log in

[mlncn]

The 403 access denied to 404 not found module is disorienting because it gives false information. It will give people a much worse experience too— if you go back to a page you've been to before, but are not logged in, you should be… told that you have to log in, not told the content that used to be there is gone.

[mlncn]

If disabling this module is acceptable, the next step is adding a login form on these pages.

[mlncn]

Lindsay:

I can’t think of any security reason that we’d need it