We are going to WDW in September and my parents are each going to have an ECV. Will they allow more than one on each bus? It would be helpful to know so I can sort of plan how we are going to get around. We rarely rent a car because the transportation system is so great. I would rather not have to deal with a car. But if we constantly have to make separate trips because they won't take two scooters, it could be a problem.