That's just it. Under the ADA Disney would not be able to limit their use to just people with disabilities. The ADA requires that equal access be given, not extra or superior access. If people with disabilities are allowed to use a Segway then Disney could not discriminate and say the able bodied could not use them too. If they have a right to use them, so do the able bodied. Besides Disney would not be allowed to ask what someone's disability is. If someone said they wanted in with one, all Disney could do is let them in. Remember a few years ago, when the offsite
ECV companies were advertising for everyone to rent an ECV to conserve their energy, so they'd have energy to party at night at Pleasure Island. Even now you are always reading threads about people renting ECVs to make it easier for them in the parks. Alot of people call them cheaters, but actually they are not, because there is no laws saying that only the disabled can rent a wheelchair or ECV and theme parks are not allowed to determine who can use one and who can't. If you show up in a wheelchair or ECV they have to let you in, just like they would anyone who showed up with a Segway.
It may not be a popular stance, but I tell you now if they do decide they're going to be allowed, I'll be renting one from an offsite company. After a day of walking in the parks, my plantar fasciitis is killing my feet. I'd love to have a Segway to prevent that pain, plus the Segways are just plain fun to ride. However, personally I do not think they should be allowed. There are too many people who would rent one that has never been on one and would have no idea how to ride one safely. As I said before I have taken the Epcot tour twice. I was lucky that I picked it up quickly and never had a problem even the first time I rode one. The second tour I took, one of the tour guides laughed and asked if I had ridden one before, because I had no problem stepping up on it, balancing it, or immediately taking off driving it weaving in and out of cones with no trouble. However, others in both tours had a pretty rough time picking it up. Imagine if one of those people had just rented one for the parks and received no instruction and were just turned loose on unsuspecting tourists.