I understand that the school has some obligation to be 'peanut free' or 'latex free', but I don't think they can really do much to stop you from doing what you want.
What are they going to do if you send your kid to school with a latex hair band? Expel her? Probably, it would go unnoticed either on purpose or accidentally. Same with a PB&J. Do they inspect your kids sandwiches or pantry to make sure that there is no peanut oil going into Jr's lunch?
They may have their rules, but the rules don't apply to you. As I told a kid I was sitting next to on the bus during a field trip yesterday when I let him play my flight simulator game on the Iphone and gave him M&M's: "The rules don't apply to me. They can get you in trouble, but not me."
I have an aversion to rule followers, especially when the rules are stupid. The kid was thrilled.