Everyone thinks China is some sort of police state, but in most places especially in the south, the local police sometimes has less real authority than cops in the US or UK, especially when incidents involved people with connections or money.

Ticketed a man who was speeding? Turns out he's a drinking buddy of the police chief at the station, and you just got reprimanded and demoted for doing your job. Arrested a woman who was acting disorderly at a high-end boutique store? She's the wife of a high ranking CCP official and you're going to be fired. Close a guy's illegal food stall? Turns out he has a huge extended family, and they all jump you off-duty after work.

This is pretty much why all speeding tickets these days there are done by camera instead of some cop standing on the corner with a radar gun. You can't bribe/intimidate/threaten a camera.