As a 4+ mile/day pedestrian, the biggest complaint I have is many of them are ridden on the sidewalk. I've had too many close calls to count. I can't wait for the rainy season to start, so I won't need to worry about them anymore.
In CA, there is a state law that prevents them from being ridden on the sidewalk, yet the police in my city won't enforce it. Mayor told them "hands off" and near as I can tell, the Mayor is working a deal with the scooter companies. Money over safety. Disgusting.