This is a huge point of frustration for me.
Helmets work. Period.
I can't tell you how many times that customers have come in and thanked us for encouraging the wear a helmet after they had a wreck.
My stance is that your personal freedom to be an idiot does not apply here.
If you are carted out of the park in an ambulance, it will certainly draw unwanted scrutiny and attention to trail access.
I have no patience for this at all. Enjoy the park, have a blast. You are not welcome in the woods w/o a helmet.