I dont know a single autistic child that screams, and I dont know how a parapalegic dancing the charleston is related at all. I checked it, and it is not illegal for them to be removed or for the sign to be on the door. It seems to me like restraunts have a toleracy of annoyance.
Babies screaming: Aww cute, but it kinda annoying
Toddlers screaming: The hell are the parents doing, torturing him
Children screaming: Take your child outside and calm him down.
Adults screaming: Get the forget out.
Im pretty sure this is the same with all restraunts, that one just had it blatently stated.