How are these shared cars not going to be treated like crap like most other shared vehicles, such as scooters? At my old college, drunks flipped a shared smart car onto its roof for sport.
The Tesla ride sharing network that's in the works (but slow-gowing in the actual full self-driving department) is supposed to be more like Uber than Hertz. If you mistreat the car and the next person reports it as dirty, you'd probably get charged extra or barred from using them if you were a repeat offender.
