I have trained to be a bus driver trainer and tail swing is a very big issue. To see what it is I park the bus next to a curb and then have the student make a hard left turn WITHOUT going forward and to monitor via the mirrors the tail going over the curb! If you have bus bays at your local schools try it when school is closed, they should have a safety line painted on the sidewalk to keeps the kids away from the buses until they load. Also our practice is to use the outside turn lane if available to keep away from other vehicles as people tend to turn in to you! Same is true on curves. had 2 buses make contact on a curve on a street. One too far to right other too far to left in lanes and tail swing caught mirrors of the one bus!
But like anything else it takes attention to be a good driver and you would be amazed at how few there really are IMO.