Well a start would be educating riders on how to safely park the damned thing when their trip is done, instead of literally dumping it on a sidewalk/pathway, and collect fines for bad stewardship.
You could have motion/orientation sensors to complement the GPS to see if they are moved after the rider parks it. It's far from unsolvable its just that nobody cares or is motivated.
Lyft/Divvy does this in Chicago. If you lock the scooter at a docking station, there’s no additional charge, but if you leave it somewhere else, there’s a small fine of $1
At the very least, Lime and Scoot now require a picture of the properly parked scooter upon ride end. I wouldn't be surprised if the other apps are the same.
You could have motion/orientation sensors to complement the GPS to see if they are moved after the rider parks it. It's far from unsolvable its just that nobody cares or is motivated.