Maybe a strong recommendation from Disney to wear them. And then a statement if you fail to adhere to their recommendations the guest is responsible for what may happen? I really have no idea.
So if someone gets Covid and dies... They can sue all the Disney guests that didn't wear a mask?
Remember.... wearing a mask doesn't protect the mask-wearer. Wearing a mask protects everyone the mask-wearer is near.
You may as well say, "people can smoke... but if anyone gets sick from second-hand smoker, they can hold the smoker responsible!"