We have used the example from Enchanted as well. That kind of explained why they look bigger or different. We have also used the saving their voice excuse. One of my dd, when she was 6, asked why Tinkerbell wasn't small in Pixie Hollow. We told her that she was small, and that we all shrank once we entered. The next year she asked the same question, and I gave the same answer. She stopped, thought and said "no. I don't think that's true." I was so sad for a minute because I thought she was realizing that the characters are just actors. Then she says, "don't you think its easier for tink to make herself big? Then she doesn't have to shrink everyone". Yes! And the magic is kept for another year!