What's wrong with this picture? It shows girls checking their GCSE results. Their head covering suggests that they are Muslim and are conforming to their religion's modesty rules. But one is not, her arms are bare.
This suggests to me that this whole headscarf business is about fashion, not modesty or piety. Educators should be careful and ensure that their pupils are not taking the piss. Most British people are so ignorant of other cultures, and this includes people in authority who, fearing to err on matters of faith and culture, go to ridiculous lengths to avoid giving offense. This plays right into the hands of the "political correctness gone mad" choristers. The wilfully offensive are supplied with ammunition by cross-cultural illiterates.

A personal note: when I was doing my national service training our platoon was ordered to spend one Sunday tidying up on the rifle range. I can't remember, but I think it was a collective punishment for some transgression.
Anyway, one smartarse piped up with "Sir, I'm a Catholic, we must keep holy the sabbath day." "Oh well", says the officer, "All RCs fall out!" It was pure bluff, but it worked, because the officer and the NCOs weren't catholics and were in the dark. Better safe than sorry, the Roman Candles skived off fatigues. But it was up for grabs; if a Scots Presbyterian had got his shout in first the dumb subaltern would have been equally at a loss. Unless one of the NCOs was a jock. My memory let's me down on that point.