Except the "authority" the FreeRegimentists here are so concerned is being defied is that of educators, arguably the group with the least understanding of responsiblity on the planet, who lack the sense God gave to a sheep.
Raising kids to obey their ridiculous rules without question will only raise a generation of socialists.
Nothing wrong with the girl and her parents trying to challenge this. She needs to do as she is told in the meantime or accept the consequences though.