I think they are related. Consider the family who takes Fido with them to Yacht Club resort as a pet (not a service animal). They will typically leave the dog in the room for up to 7 hours and go to the parks. At some point during the vacation, they might say, wouldn't it be fun to take Fido with us tomorrow to Epcot? He will love walking around with us. No problem, Fido the pet morphs into Fido the Emotional Support Animal for Epcot day.
Of course not every pet owner will do that, but I contend some will. I think that's why some are reporting a recent uptick in dogs in the parks. As the population of dogs at the resorts increases, it becomes more likely that some of those owners will attempt to bring their dog into the parks. Just my opinion folks.
Another possible scenario: Over the course of the week, the dog owner might start feeling guilty that they are leaving the dog alone in the hotel room all day thus tempting them to take the dog to the theme parks with them. Or instead of guilt, perhaps the owner finds that the dog is barking a lot, or urinating in the room, or chewing up the mattress because of boredom or fear.
Disclaimer: I believe that service dogs and ESAs provide a valuable service to those in need and I support them. I am fortunate that I don't need one. However, I do think that there is an increase in people declaring their pets as an ESA. As this abuse increases, I think their might be a backlash or overreaction in legislation on ESAs such that those with a true need for an ESA will be negatively impacted.