I'm not arguing the logic of it, simply stating that, to my knowledge, it's a blanket practice. Discussion, and counter-examples are welcome.
http://employment.americanapparel.net/employment/index.asp?c...
Edit: This would lead me to believe the law is somewhat up for interpretation and it's not cut and dried, since AA is a pretty big company and I would assume their legal dept had to sign off on this kind of thing. That being said, they are pretty well known for being sketchy and creepy.