> but over here we tend prefer for the government not to swing its weight around until there is clear evidence of a problem.

There is clear evidence of a problem: SF banned scooters to give itself time to figure out how to regulate them: http://www.sfexaminer.com/companies-pull-scooters-off-sf-str.... There is no reason to think SF is particularly unique and that other municipalities won't have similar experience.

And even before SF banned scooters, there was clear evidence of problems with dockless rentals in China: sidewalks became bike parking lots with little room left for actual walking.

This idea that governments should only regulate if there's a manifested problem in their particular jurisdiction is pretty stupid, frankly. It's like saying you shouldn't make up your mind about crack cocaine before you've actually tried it and experience the problems it causes.