I think you're right that outright theft of the car is unlikely. But the advantage that Zipcar has over this p2p system is Zipcar personnel can keep a log of ev

I think you're right that outright theft of the car is unlikely. But the advantage that Zipcar has over this p2p system is Zipcar personnel can keep a log of everything related to a vehicle - the condition of all of its parts and a full inventory of its accessories. This also allows Zipcar to make final decisions about who has caused damage or theft. In a p2p system, there is no central authority to adjudicate these issues - which requires relying on the word of either the owner or the renter to decide who is responsible.