Most of the potties are "auto flushers". My DD was terrified of them. At MK, we had to go to the child care/ first aid center to use the potty...they had the normal flush type potties.
She needed help getting on/off most potties, even at the child care/ first aid place.
When we were at other parks we tried to use the "family" restrooms whenever possible. They are larger a single separate restroom with a locking door. They did have the auto flushers though, but at least I had enough room that I could hold DD over the seat while she "went", lol.....poor thing, she thought she was going to get flushed every time she heard that big WOOSH!
I also remember hearing that if you put a sticky note on the flusher sensor, that it won't auto flush....never tried that trick myself though.
Have fun!
Jennifer.