Chinese Police are coming to your country?!?!
I think the California guy will be acquitted. The state law defines what "peace officer" is, which means California Highway Patrol, county sheriff, municipal and district police, university police, correctional and probation officers, and federal agents.
The law does not contemplate foreign police agencies, as they have no jurisdiction or power in California to begin with.
He was driving a car that says 公安 (public safety, not 警察) does not probably establish guilt.
If a classic car collector bought an old British or German police car and drove it in California, with a valid California license plate that does not start with a letter E (as in Exempt, i.e. government vehicle), cops won't do anything.
Likewise, if a Hollywood film production drove a fake prop police car on highways to a filming location, that is entirely permissible too, even if it may intimidate immigrants along the way.
What the guy did was mean and stupid, though.
Movie prop cars also display a decal (magnet that sticks to the car) that identifies the movie prop company, but that's hard to notice from distance.
Of course their license plates are real and standard ones.
One thing these cars are not allowed to have is blue flashing lights (prop cars use white lights, which will be turned blue using computer during edit).
There used to be a prop car company near I used to live and those cars can fool people from across the street.
"I appreciate SDF but it's a general-purpose server and the name doesn't make it obvious that it's about art." - Eugen Rochko