Must be some extremely poor quality. I had a good luck thing when I played one year (switched yearly it seemed like). If we won I didn't let them wash it...if we lost I did let them. They got washed a lot.
I had another good luck thing regarding the shirt under my pads. Wore the same shirt for an entire year. Never washed it (went undefeated till the championship game). After a while I would open the locker to find my shirt in a petrified state. Had to rinse it in water to get it to loosen up so I could put it on.
My girlfriend found it after the season. I didn't see her for a while