As a current WDW bus driver, I will tell you how Disney operates. The speed limit in the load zones and parking lots is 5 MPH. Stop signs mean a full and complete stop. Resort gates (whether they are open or closed), require a full and complete stop. Just 1 MPH over the posted speed limit can an has resulted in termination. We are just doing what the law states. If your livelihood was driving, you would follow the law so you didn't lose your job. The operation of that Disney bus falls under MY driver's license. I am responsible for everyone onboard and I personally don't want a collision to end my career at Disney. I will pull over if children are running around while the bus is in motion. Nine times out of ten the parents are playing on the phone paying them no attention (please mind your children). I will, and have asked guests to get off, and management will stand by the driver if it is a safety issue. Ad don't forget, strollers MUST be folded. Not my rule, it's a federal regulation, so please don't argue with me. Arguing with me will most assuredly be the reason I don't let you board.
There are Disney drivers that I feel drive WAY to slow. I do the speed limit when it is safe to do so. I believe that my guests paid to be on vacation, not stuck on my bus for an extended period of time. All of the routes that we run are they way Disney wants us to go. Those routes my seem longer, but they do avoid as many traffic lights as possible and offer the safest turns at controlled intersections to avoid being broadsided.