Autonomous vehicle systems are a lot more fragile than given credit, and engage much more in tragedy of the commons than they purport.
If I wanted to monkeywrench Waymo, I might arrange a group of similarly thinking human beings, maybe a dozen would be all it takes, to randomly, periodically arrange Waymo trips and upon exit leave the door ajar. Coordinated effectively, would have the same end result as the recent SF power outage, stranding robocars throughout the city. I mean heck, if I was one who got paid to unjar the doors, I might cynically enlist others into such a scheme if simply to create more revenue for myself.
My words are a philosophical speculation in the act of free speech, and I am not encouraging anyone to act upon my musings.