I think this is why crime is "falling" in San Francisco. The cops make no arrests, and often don't even take police reports. A few months ago I and everyone else in this store got pepper-sprayed by a shoplifter (the way the security guard told it, a shoplifter attacked a guard with a large can of it which ruptured when he swung at him with it and hit a shelf). I don't even think the police showed up. They weren't there 20 or 40 minutes later when I drove by after going home to clean up.
My business partner used to watch burglars in Pacific Heights go door to door and steal packages out of apartment building lobbies. He'd call the police and they'd say thank you but never even sent a car.
I was in a hit-and-run accident a few weeks ago, and because I wasn't injured, it was "just a misdemeanor" and they categorically refused to take a report at the station, even though I had dashcam video and the plate number.
The SFPD is pretty much entirely useless.