That's the problem with the celebrity endorsement, one of the mainstays of American marketing, sooner or later everybody does something stupid or worse. In today's world where we all live in glass houses, there is no place to hide. So before you hop into bed with the movie star du jour, sports legend or musical genius, you may want to know who else he or she has been sleeping with. Better yet, figure out how to make your brand famous without borrowing fame from someone else. The reputation you save, may just be your own.