If the school board is fearful of lawsuits (admittedly, they probably know their students' parents somewhat), having those parents sign a hold-harmless agreement would certainly be out of the question, too, because that would take away the parents' and childrens' rights, correct? Certainly can't have that either; it would cause them knee-jerk revulsion.
Oh, what a tangled web the Left weaves with the Mommy State!
HF