If they're a problem it'll be if someone rides on the sidewalk, but I've personally yet to see that.
Frankly SF has dozens of other nuisance problems such as literal human feces on the street, tents, crack smokers in broad daylight, various types of property crime, before one tipped-over scooter in a 3 block radius would be considered a legitimate nuisance.
I think the main reason why the city is going after these startups is because the startups have money.
MTA a few years ago dealt with bicyclists ignoring "Dont chain your bikes to X" signs by sending its workers to cut the bikes in addition to cutting the lock chains. This quickly solved the problem.