Really, it is up to the individual to have made sure they know how to safely operate an ECV in a crowd, but I would say 90% of the time the issues have nothing to do with the ECV driver, when I have needed one, I have been pulled off to the side of the road, completely stopped and someone runs into me and cusses me out, even though I am out of the way and not moving in any fashion.
Additionally, people seem to be under the impression that mobility devices stop on a dime, and while the ECVs that Disney rents now do, one of the reasons I would never recommend one of them, most don't because stopping on a dime tends to injure the person riding them, many of whom already have preexisting conditions that would be made even worse. It would be far better for people who are fully mobile to see people in mobility devices (manual or powered) and move out of their way instead of expecting the person in the mobility device to move, this is even more true with manual devices where they may be exerting a lot of effort to power them up a hill, etc. Now you want them to stop at the last second or swerve around someone who decided to jump out in front of them, this isn't always possible and people on both sides need to be more aware of their surroundings, but the bulk of the responsibility does need to go to the people not using mobility devices as it is easier for them to move.