Watched one of these block traffic once by putting on its blinker to turn down a street with a police barricade up. The street had been closed and the police weren’t going to lift the barricade. Nonetheless, the car put its blinker on and sat there blocking traffic indefinitely.

The motive was that the car drove down a crowded Chinatown street during Chinese New Year. I imagine something similar might happen if a human driver tried to do the same thing. Not saying the vandals were right to wreck the car, but you don't just creep a car down a busy street during a festival and expect nothing bad to happen to it when crowd mentality/anonymity takes over. Especially when there's no driver so no immediate consequences/accountability. I think it was quite fortunate that it was not transporting a passenger at the time.

There is a small group concern taking the law into their own hands, yes.