What about car theft?
The other problem is car theives. This goes back to when cars became difficult to hot wire or break-in for stealing, criminals were simply car jacking people to steal cars. With this system could thieves simply "borrow" cars to use for crimes to cover thier criminal tracks? Once one rents a car you still have to trust the person who uses it. With all the technology being used to monitor the person renting these cars this process won't make the person behind the wheel honest or keep that person as a responsible driver.