You're right. The "marginal difference", as you say, is key. So let's assume theft of parts happens rarely. Don't we still need a process in place to adjudicate when it does happen? Let's say the theft is not of a water pump but a car radio or, let's say, the owner left his radar detector or his daughter's ipod in the car and the renter walked off with it. What's the process for adjudicating that claim? Does getaround need to get involved? What if it's a false claim and the renter is unfairly charged for it? The same applies to scrathes and damages. If the owner claims the car was scratched during the rental, does he need to back up that claim with photographic evidence - before and after pictures? And what's the process for authenticating those pictures as valid? All I'm saying is there's a minefield of potential disputes here, especially because there is not necessarily a hand-off between the owner and the renter when the car is returned.