Apparently, Facebook allows its employees to eavesdrop on the comings and goings of members. I said "apparently," because Valleywag reported this, meaning the whole thing could be a fabrication.
Anyway, it sounds plausible, so here's what Valleywag said:
Facebook employees can (and do) check out anyone's profile. Not only that, but they also see which profiles a user has viewed -- a major privacy violation.
Reminds me of the stories about IRS agents snooping on tax returns of friends, relatives and celebrities. Not as creepy as the IRS, but a company valued at $15 billion shouldn't allow this kind of crap.