We haven't exactly solved that issue for human drivers. People impersonate police in order to commit crimes.
How much more problematic is it with autonomous vehicles? I could see action here just because it is a threat to the property of large corporations, though.
People exercise coordination ability like this all the time.
I got stuck getting out of shoreline after a large concert with abnormal parking conditions, and when we didn't move for 30 minutes I got out of the car and directed traffic so both lots could empty equally. Took another 45 minutes for my family to catch up to me, which was good because that's when someone in a safety vest showed up and told me to stop.
How much more problematic is it with autonomous vehicles? I could see action here just because it is a threat to the property of large corporations, though.