Something that I found pretty interesting is that I tried to let me 4 and 2 year olds ride the butterflies by themselves. My oldest is definitely over the "ride by yourself" requirement, and I measured my youngest at home and he appeared to be right at 36" or so. However, the guy measured him, and he said he was too short to ride without an adult. We went and measured him ourselves after the ride and sure enough, he was like an inch and a half short or something. I thought that was weird, but just thought I measured him wrong at home.
So last week we were in San Antonio, and we went to Sea World. Measuring him again, Sea World's chart had him barely below 36". He was wearing the same shoes both times, and these times were only a couple weeks apart. Doesn't make any sense to me.