In our experience they are super strict! Our daughter was refused several times even though she was JUST under. For Disney, it's an insurance and safety issue. If they let kids on and something happens, they're facing a lawsuit. I've seen people try to put their kids in thick soled shoes and all sorts of things but for the most part, CM's spot the tricks and say no anyway. I would be prepared for her to be refused and explain to your child before you even leave that if they are not tall enough, it's not safe for them to ride. We found this reduced the tantrums!