I heard about a GSI at my school that was trying to look up one of their female students, and accidentally typed the student's name into the "update status" box instead of the search box. They got flustered, didn't know how to undo it (because it would probably stay in people's feeds even if you deleted it), so out of desperation they decided to disable their account to prevent it from being seen. The next day they remembered their facebook was registered under their undergrad e-mail address, which they no longer had access to, so their facebook page was gone forever.