Nobody knows how any of this is going to work, and perhaps not even Tesla has worked out those kinds of details.
So perhaps more importantly, what would YOU like to be able to do? What would make you comfortable with loaning out your car? How could the internal camera help you?
As far as charging passengers for damage, it's assumed that their credit card would be stored with the Tesla Network, since that is how literally everything works these days. From there, it's a matter of developing a seamless way for owners to report damage and quickly reimbursing them for it. Since the car may be going from one rider to the next, the only way to know who did something would be to review the footage later once damage was discovered. That could be a lot of footage to review - ideally it would be on some kind of cloud-based platform where you could quickly find the incident by scrubbing through video, type in a quick description of the damage, and click send. Of course it doesn't need to be that elaborate unless damaged cars is a widespread problem.