My high school banned damn near everything--baby tees, white tees, spandex tights, tight pants, spaghetti strap tops, skirts and shorts above fingertip length, cellphones (they were expensive and luxury back then, I can only imagine the problems they're having now that EVERYONE in the class has one and not just one or two people)...normally was a cluster of people that caused the problem for everybody, and if the person in charge didn't get it, the item was banned.
While I was in school, I did feel that they should have focused more on the curriculum and ENCOURAGING students to present themselves a certain way, and less on what they were wearing and banning it after assuming it was a distraction to learning. Controlling things like makeup and accessories is an attempt to control outside influences, when the school would probably benefit more from setting a basic dress code and treating isolated incidents, because 9 times out of 10 the issue was WAY bigger that who was wearing what.