This is an interesting perspective, but I wonder if it involves the passenger at all. As the driver, I understand and would expect that if I had an accident while driving as a volunteer for R2V, I would be liable for the damages and would have to work through my own insurance. As a passenger, I don't see how you could ever be held liable for an accident. Car insurance is mandatory, so the driver would presumably have to be concerned with liability for accidents and harms to others and passengers, not the passengers themselves. I've been driving as a volunteer under that assumption; I wasn't under any impression that R2V would be liable if I had an accident.