Thanks so much for your response. It certainly makes me feel much better. I feel confident if there had been problems with this kind of thing before, it would be well known on these boards. My DH and I usually try to spend only cash (traveler's checks) while traveling, but I know that we can pay cash at the end of our stay.
We both like the idea of using the room key for everything and not worrying about having cc or id with checks on us all the time. Plus, it is a good point that we could allow the 14 yo charge privileges if we want to.
Just to clarify, can we charge absolutely anywhere on grounds with the room key? Parks, CW, any hotel, pool, etc?