I suspect I may get flamed for this but I genuinely do not get it.
They have a rule against earrings including sleepers. That I get especially with younger children or in sports were children can end up getting them at worst ripped out.
I can kind of even get extreme haircuts with big shaved stars or strange styles that look unprofessional and might not be allowed by adults in a professional work place.
But this week and last term several of senior age children who had dyed hair brown/red/dark purple etc were sent home from school to re dye or put in isolation by teachers with errr brown/red/purple dyed hair! One of the children's teacher has bright purple hair. It does not make her any less of a English teacher or lesson her professionalism in school I don't reckon so what is the problem for teens?