Okay... I'm going to add my two cents to this topic...
During my career, I've seen all types of guests. I've seen the guests with the compact foldaway stroller, that can board a bus or a monorail quickly, because they're organized, and prepared. I've also seen the guests with the jumbo stoller that wait till the last minute to get everything together, folded, and take forever to board the bus because they are so unorganized. Now, I am just as friendly to both parties, however, I greatly appreciate those guests that are organized, prepared, and think ahead. As such, I'll be more than likely to do something extra for them. (ie: a Bus Driver card for the little kids, or something like that)
On the topic of guests travelling with wheelchairs, or guests that may need special assistance... In this department, I've seen it all as well... I've seen guests using wheelchairs for shopping carts... (and while I understand that some folks might use the wheelchair as a walking aid... this wasn't the case)... I've seen guests (admittedly) use wheelchairs for strollers for able-bodied kids... I've seen guests who legitimatly need an ECV, get out of the ECV, sit down on a bench, and let thier 8yr old grand son drive the ECV as a toy. I don't think I need to remind anyone that they are not toys by any means.
On the flip side, I've also seen guests traveling with wheelchairs that preferred to get out of the wheelchair, decline the lift, and struggle with the bus stairs... just because they didn't want to inconvenience me, or perhaps, they wanted to be like everyone else. I have guests all the time who travel with thier own mobility device, or use rented mobility devices. And they have them because of a legitimate medical reason, whether it be apparent or non-apparent. I'd say most people use mobility devices because either they need them, or it makes travelling through the parks easier for them. But unfortunetly, there are those folks out there who abuse the system, and it's those folks that I get upset with... not those who have legitimate reasons. At any rate... I always treat my guests using mobility devices with the utmost respect, and friendliness, and I try to accomodate them as best I can.
Now... I do have a few more things to say on this topic... and I'm hoping that I won't get flamed about this...
I do understand that guests with disabilities should be given every oportunity for a magical vacation that everyone else gets... and maybe even some special treatment to add that extra magic. I also understand that there are situations that may need special accomodations. That's fine. But is there such a thing as accomodation going too far?
I know a common frustration for guests is that other guests travelling with mobility devices and thier parties would get instant access to rides, bypassing all the lines. In response to such frustrations, Disney has started to make a lot of queue lines fully ADA accessible, so that the guests wait thier turn just like everyone else. While most people that I've encountered (Both able-bodied guests, and guests with disabilites) agree that it's only fair, I've heard from a bunch of guests that wish it was back to the way it was, simply because they think WDW should bend over backwards for them.
One situation I had when I worked in Monorails... I had a family of four up front... 2 parents, and 2 little kids. I was about to leave, when a family came running up the ramp, so I held the train. They came all the way up front, stepped right past me, got into the cab, and demanded that the other guests get out. (Mind you, these guests had already waited 2 trains to get in the front) Thier reason? Thier son was part of the Make a Wish Foundation. Now don't get me wrong... I will go out of my way to accommodate Make A Wish kids, and try to make thier vacation a memorable one. I think the Make a Wish Foundation is a great organization. However, It does not give one the right to kick someone out of the front cab... They need to wait in line, just like everyone else. I'm not being mean, in fact I tried to be as cheery nice and friendly as possible when handling this akward, delicate, and strange situation. As it ended out, the guests who had waited 2 trains already, got out voluntarily... and waited for another train.
Unfortunetly, when dealing with ADA... it's a very very very delicate situation... and sometimes... you just have to bite your tongue, and accept what's going on, even if you may not like or agree with it. Me personally, I don't let the abusers get to me... rather, I take that energy, turn it into positive magic, and feed it back into creating the most magical vacation for those who deserve it.
To person who feels that the only reason to rent a wheelchair is If you get hurt, are suffering from heat exhaustion or are old, not to sound nasty BUT 
