Pointy Tail of Satan: if your car while in autodrive runs someone over, who is going to prison? The driver, the car, or Mercedes?

In a level 3, the driver is still the person with responsibilities. Which is why you would want to skip directly to level 4 or 5. At those levels, there are no human-controllable interfaces like a steering wheel or brakes. In those cases, it will be the manufacturer's responsibility. They can claim that maybe the sensors were out of alignment or something, but the car can't start until a complete check of all sensors and their proper positioning, and all sensors pass the check. Current AVs like Cruise, Waymo, or Zoox have external sensors. People can (and do) walk by and whack them or give them a roundhouse kick. Once that happens, the vehicle is not allowed to transport people or things. The vehicle may return to the garage on its own, autonomously, or a tow can be assigned to bring the vehicle back.

In the future, the sensors will be internally mounted so there's nothing sticking out for pedestrians to walk by and damage. With tinted or mirrored windows, nobody would ever know the vehicle is autonomous.

I have ridden in a Cruise AV and we see a box or something out in the middle of the road. The AV slows down as it approaches the box, then goes around it. So it knows not to run over a person or cat or box. Now, if the person is playing chicken and daring the AV to run into him, well, first off the AV would just stop. After the person tires of playing chicken, the AV will proceed. Second, there are also external cameras so if someone is playing chicken, the whole interaction is recorded and there is no chance the person can win a lawsuit.