They don't come much slimmer than my DD, who usually comes in at the 50% for height and 10% for weight. If she complained about having to walk, I would solve that issue by taking her back to the hotel. Giving in to complaining would not be an option. Heck, it isn't an option at home so why would I be held hostage to it on vacation? If she is too worn out to walk, then a good long rest is in order. I would just tell her we could come back when she felt up to walking.
A few years ago, we were meeting friends at WDW and they had a child who was prone to complaining and whining. DD is not, but on the off chance such behavior might be contagious, we told her before we entered the gates, "Odds are, Chris is going to whine and complain and try to get his/her way most of the day and that it will work on Chris's parents. We don't think you would ever act the same way, but just in case you decide to try the same thing to see if it might work for you, we want to be clear. It won't. It will get you the opposite of what you want. So if you are tempted to whine or complain like Chris, you need to understand that we will not hesitate to stop whatever we are doing, walk right out of this park and go back to the hotel for the rest of the day."
She never did complain or whine (we didn't think she would) but Chris did. And the parents frequently gave in. Which is probably why Chris kept complaining.....works like a charm.
