I also want to add that I think that if the parents really don’t agree with a school policy but pretend that they do, then they are being dishonest and giving the kid a contradictory message (since they are saying one thing but thinking another), and that is much more likely to confuse the kid than if the parents and school have different opinions.
That is my real issue with such a policy. They don’t necessarily have to voice their disagreement -(that would be my approach, but I could hear why some would disagree)- but they shouldn’t lie and say they agree when they don’t.
I think it’s much better to be open.