One of the problems with school dress codes is that they are not equal nor enforced equally. For example the boys can't wear short shorts yet the girls can wear mini skirts. Girls can't wear open toe shoes yet boys can wear flip flops.
Obviously not all schools follow the same dress code.
Our school district doesn't allow mini-skirts, flip flops, tank tops, tops or dresses with spaguetti straps and the list goes on and on... The schools here do enforce the dress code, my neighbor's daughter had to go home to change when she wore a mini-skirt in 6th grade.