The one time when we went to the local park in our area (Valleyfair), we had to stop at Guest Services and fill out a pretty detailed questionnaire about DD's abilities. I don't know if they still even do this, but all we got out of it was a list of rides that she would NOT be allowed on for safety reasons.
On one of the rides that was not on our "forbidden" list, we got in line (seen by the ride attendants), got all the way to the front of the line and found a turnstile. With no other way out, we had to back all the way out of line. The attendant said she hadn't realized a wheelchair wouldn't be able to go thru the turnstile!
Things like that make me happy to go to WDW. Even when things don't go well, they still are WAY better than anywhere else.