As WDW is private land, they are allowed to kill gators that have become a nuisance. If they do that, they would probably do it by hiring one of the many companies in Florida that will remove them for a fee. The companies then sell the gators to a processor, which is quite profitable, as a large one can bring in about $2K for the hide and meat. It's not legal to kill gators found on public land unless you have a permit, and those are VERY hard to get.
They may relocate the animals to a remote part of the property, but that isn't very effective if they have been hand-fed; they will find their way back to a populated area. If WDW gators are actually relocated to public land, my guess is that they are probably taken out to Cape Canaveral; the area around NASA is a wildlife refuge.
Just to be clear, I don't think that the only good gator is a dead one. What I did say though, was that any gator that loses it's fear of people and starts hanging around in a populated area will become a public nuisance. Once that happens, death isn't long in coming, one way or another.
