Here is their website.This. I don't doubt that this company exists--taking advantage of people with more money than common sense or morals--but a simple internet search would tell you that a GAC card is pretty easy to come by. You don't even need the kid, "oh, he's with mom." At the end of the day, I'm sure the "free" abusers of GAC far outnumber the number hiring this tour company.
I do know there is also a "black market" for Give Kids the World buttons. Same idea, unscrupulous people trying to beat the lines (not that the parents of the terminally ill kids selling them are any better).
If something can be abused, it will be.
http://www.dreamtoursflorida.com/