Why on earth should a school be able to order children into what they wear? Obviously it makes sense with regard to outright offensive clothing or whatever, but I don't see why schools should be any more intensive.
Children are born, pressed into these institutions for as long as they can remember, are there from early in the morning til early evening, then have everyone expecting them to work at home as well. Oh, and they're going through puberty, living in a vicious and judgemental social environment (the playground), dealing with all the inevitable insecurities etc. AND they have adults barking down at them if their dress isn't perfect because of some vague and arbitrary notion of 'school pride'.
What a ridiculous and outdated notion. This idea that kids should all be wearing the same uniform seems to confer absolutely no benefit to anyone except a few adults who get to watch all the children file into assembly and think 'gosh, look at how neat they are.' Adults who, incidentally, have nothing even remotely approaching as strict a uniform policy, and are paid to be there. Is there really any serious evidence that a strict uniform policy decisively instils discipline into children? Really? Is it so unreasonable to just let children wear what they want to - within reason, of course? I don't think so.