There is rules at our school too, Girls are only aloud one ring on each finger, If i wear one i get it took off me when girls totally disobey the rules and wear about 30 on each finger ( the chavs ) Also there are no rules on hair really i have blonde streaks and nothing gets said!
Just live with it its the rules!
Edit, My tutor always tells me to take my hoody or jacket off before any other student! Especially the people who get bummed by all teachers because they can do subjects better than any other student!
Discrimination is a serious thing, If it goes any further it could turn into a big thing, Be sure what your doing with these things!