Also, you may have noticed, even 'invisible' members can't hide completely from non-mods. On the "Who's Online" page, even if you can see only, for instance, six usernames and their activities, it still says "7 members online." So it takes a little bit of deduction and Hoosier ingenuity to figure out who the 'invisible' member is.
Makes for a fun game.
"Who is the INVISIBLE MEMBER??" Dun Dun DUNNNN!"