When I click on a link to an admin page on a site where I'm not a moderator I see a Moderator Agreement page instead of a 404 page.
Example (using my own UserID):
Clicking on https://stackoverflow.com/admin/show-user-votes/3536342 displays:
The URL gets redirected to:
https://stackoverflow.com/legal/moderator-agreement?ret=https%3a%2f%2fstackoverflow.com%2fadmin%2fshow-user-votes%2f3536342
Note that I'm a moderator on Super User, not Stack Overflow.