I have the one you are talking about. I told all the parents I was getting one but don't have a waiver form for it. If it was a bigger outside one I would probably do that though. Wouldn't hurt to have one anyways.

My rule with the indoor one is that they can not be on it unless I am in the room (usually I am sitting right beside it to help them off and on). I put it away when not in use and they can not get on it without me knowing.