No, but tiny short skirts and tank tops with half your breast hanging out (Which I have seen people wear to school) are not really needed either, are they? Same with guys and there boxers hanging out and "wife-beaters" (I do not know the actual name of them, if it is not that, just what I have heard them referred as)
At school of course, where you go to learn your subjects and how to react in a social enviroment, shouldn't there be some form of class enforced, so people do not think "hey, it is OK to wear tiny revealing clothes in serious situations!"