I took the judgment out of this so that I could respond and focus on my response.
I agree with you that I dislike that bus drivers ask people on scooters to transfer to seats when they've just taken up 3 seats with the scooter. I fully believe that they should be able to remain on the scooter during travel.
When I required the use of a power wheelchair because of MS (and yeah, I was overweight, but I dropped all that weight so I don't think I qualify in your Jumbo category anymore) they forced me to remain in the wheelchair (which was fine cause I couldn't get up anyway) and put a seatbelt on me. This made me laugh because my chair is strapped down and I am belted in to the chair and then I was belted again to the bus. Meanwhile, the 4 year old on the seat in front of me has no restraint.
I also feel that instead of placing the scooters in the middle of the bus, I wish there was a way to load in the back or the front as I believe, imo, this would alleviate some space issues, but with the way the buses work I don't know if that's possible.
The bus driver is not making them transfer to cause anyone more grief, it's for safety. Scooters are not safe with a person on them and a moving bus. While the scooter can be strapped in, strapping in a rider on a scooter is WAY more difficult than a wheelchair.
Usually a guest in a wheelchair will be asked if they can transfer and allowed to if they can. You were in a power chair, 99% of the guests in a power chair will remain in it, so I can understand why you were belted in but he should have asked and given you the option of transferring.
The 4 year old in the seat unbelted is not required by DOT to be belted in on public transportation, a wheelchair bound person who remains in the chair, is. In this, if you have an issue with it, take it up with the Federal DOT.
While certain bus configurations will allow different tie down locations, the buses Disney has standardized on are only suited for the current locations. There was at least one Nova that had 5 tie down locations. You think the current locations are bad, that one was worse if you used any of the alternate tie down points.