Edit: I can think of a way. These things move in a regular traffic. To drive a car, I had to do a driving license. 40 hours with an instructor, a theory test, and a practical exam. How come any clueless chimp can get one of these and ride in traffic? They are dangerous to themselves and others. It’s a celebration when they wear a crash helmet.
So here are my ideas:
1. Require a license for these things.
2. Collect and remove illegally parked scooters. Rental companies know who rode one, they can claim the cost of a scooter removal fee from the rider who parked it illegally. If they are concerned about people randomly moving scooters into illegal parking positions… well, come up with dedicated parking areas where the rider has to bring them back and lock them.
Until then: ban them.