I just read a trip report from a family that went to Tokyo Disney and they said that every child got an "official" measurement when they entered the park, then wore a colored wristband so CMs could clearly see their height. It seems so sensible! One measuring stick, one place, no waiting in line to see if you'll be let through, no one CM letting you on but another CM saying no. I really wonder why they don't do this in the States.