This is unbelievable. With all of these studies showing up that employers/schools use public social media channels to make a decision on applicants, this is way over the top.
It is worse than that -- say you are friends with some former coworkers on facebook (because well, you actually like them) and they then show some other company their facebook page while interviewing there. They might or might not hire them, but even if they do, they have seen private stuff that you might cause them to not hire you.
Hopefully this ends fast.