I know they're out there but the only cop bars I've ever seen are on TV
I was there once with one of my Marine buddies (both of us very well lubricated), when he took exception to some knucklehead who was "exaggerating" his military experience. I had the pleasure of watching a five-second demonstration of open-hand fighting technique. My first reaction was "if these cops get up, I'm screwed." My second, "will I be out of the jail/emergency room in time for my brother's birthday party." My third, "why are these cops not getting-up."
Turns out that the guy getting pummelled was not a cop, and some of the cops were Marines themselves.
Here's the interesting thing: after the fireworks, one of the cops gets up, walks over to me (I haven't moved), and says, "You guys can't stay here. Do you need help getting home?"
--some criminal genius attempted to rob a cop bar in Las Vegas a few years ago and died in the process--the only officer to shoot him did it with a .25 ACP, IIRC---