We were just there this past November, DTD location. I tried to tip my daughter's fairy godmother, but she would not accept the tip. I tried a second time, and she said, no thank you, we are not allowed...
I had asked the same question before my trip, and I was told that yes, they do take tips.. I think it may be something that changes often, or maybe a rule that is only enforced occasionally..
I guess it wouldn't hurt to try....