I worked with someone who had previously worked on park robotics, and apparently they had to guarantee that the character could not injure a child to be able to put them in parks - a particularly high barrier to actually doing so.

One look at Olaf's hands alone make that an impossible thing to guarantee. Those stick fingers will eventually poke a kid in the eye if kids are allowed to get close to the character. If they gave him a small intimate stage, or roped off area, to do some act or crowd work that would be more ideal/less risky.