I am in agreement with the others here. Your son needs to find something else to wear. The rival school thing is the biggest reason. I'm not sure how big the rival thing is in your town, but just my experience...rival means just that- rivals!! They do not like each other. Your son would possibly be harassed or teased or even hurt, physically. The other reason is because this is something of yours you do not want ruined. And sometimes, the answer is NO! Hopefully, he will just accept that. It's really cool that he likes band and this is probably a group that accepts him well just for who he is.