If you leave a car “laying around” in a spot not designated for parking a car then it’s likely to be towed, or at least ticketed. This works because the car usually has a registered owner who wants it back.
http://nordic.businessinsider.com/contentassets/15ba9de498c2...
This is a snarky but accurate restatement of your (commonly professed) belief.
i do agree having regs to dissuade people from blocking & riding on the sidewalk with scooters seems very reasonable.
once you have that i think scooters are basically problem free (except for maybe aesthetic concerns).
even w/o that, i still don't see how anyone reasonable could think scooters were anywhere near the top of the list of hazards of sf streets.
(perhaps they are a major inconvenience for wheelchair users?; i'd be interested in any first-hand accounts.)
Cars have all the problems you’ve mentioned and more and I’m also dissatisfied with how much public space we’ve set aside for them, but they also mostly stay off sidewalks and wait at street crossings, so at least we’ve also set aside space for pedestrians to get from one place to another that is usable even for those in wheelchairs.