I actually have experience that runs opposite to this. Our trip to WDW was what finally got my oldest potty trained. The fact that the bathroooms were very kid friendly and for the most part very clean meant he was excited to use the bathrooms at Disney. For the longest time he hated going #2 but it just seemed to click at Disney with the themed bathrooms. He came in pullups and left in big boy underwear. For him it was another attraction.
Wow, uh, no. Once my kids were potty trained diapers were a thing of the past.
Disney is about the most convenient place to travel with small children. There are multiple rest areas to stop at. Honestly I think it's pretty lazy parenting to do that.