RelayRides changed its name to Turo in 2015. Today it claims nearly 150,000 cars on its platform, which includes many vehicles at airports, though it declined to describe how active those owners are. Getaround would not disclose exact numbers, except to say that there are thousands of cars in its major urban markets. It counts owners who have made their cars available in the past month.

That’s not nothing, but putting your car in a rental pool is clearly far from a reflex for the vast majority of people. Some of this is practical, since if you commute each day, it may not be easy for a renter to get to your car when you’re at the office. On the weekends, most people want flexibility for leisure, errands and family rides. Also, while homeowners have been taking in boarders for centuries, the possibility of effectively turning your vehicle into a Zipcar wouldn’t have occurred to most people until the first Zipcar appeared in 2000.

A search of the internet and court filings suggests some other potential problems. In the comments on a first-person blog post on Travel Codex about car theft and Turo, I found Ryan Root. He put a Jaguar on the Turo platform last year, and told me in an interview that it was damaged three times (and totaled once) during 29 rentals in Bayonne, N.J.

Because of “limited availability,” said a Turo spokesman, Steve Webb, no one was available to talk to me on the phone. He said via email that less than 1 percent of Turo rentals result in damage.

One of Turo’s own insurance partners filed suit in federal court last year over another death. In that instance, a Turo vehicle struck another car and killed its driver in Smyrna, Ga. Brian Lewis, a lawyer representing a passenger in the Turo vehicle, said that the Turo renter was not the person actually behind the wheel, and that the suit would resolve the question of whether Turo’s insurance ought to cover that situation. (The lawyers for the insurance company did not respond to a request for comment.)

In an email, Mr. Webb said that the Turo vehicle in the Smyrna accident had been stolen, that the insurance company does not believe it owes coverage to a criminal, and that the coverage would indeed protect the car owner. He declined to provide overall theft figures, though he did say that it was “extraordinarily rare.”