We took our little ones on anything they could ride before they knew there was anything to be afraid of (like HM). Julia got scared on Alice in Wonderland, because of the screaming queen. We started calling the queen fathead, and that made Julia laugh, and then she loved to ride it. Same with Brendan and the whale on Pinocchio. We made jokes about it, and that reassured him, and then he was fine with the ride.
When we were at Blizzard Beach, there was a mom dangling her child over one of those huge, straight down slides. The kind that when I go down, as I sit I ask myself why I am going on. The poor kid was flailing and crying. IMO, that was borderline abuse. Thank God the lifeguard finally told the mom she couldn't put the kid on the slide, and they had to walk back down the line.