I'm not a cop, but this happened to me, and the cop that showed up said it was the dumbest thing he has ever had to respond to, so I hope it makes the cut for this thread...
I used to manage at dominos pizza in a fairly bad part of town (college area, mixed with pockets of ghetto) and one day during lunch this guy comes in and right off the bat I know he's going to be a problematic customer, the kind that searches for things to bitch about to get free food. So I take his order, and go wash my hands to start making it. I wash my hands, and then go to the dough to slap out his pie.
He yelled at me and screamed that I wasn't using gloves. we don't need to wear gloves when making the food because it is then run through an oven at 400 degrees Fahrenheit for 7 minutes and that is enough to kill off any germs that might have made it onto the food via our hands (that I habitually wash before and after every pizza made - I hate having food on my hands). Obviously once it comes out of the oven, we can no longer touch it with bare hands. I explained this to him and he yells "NAAAAW MOTHERFUCKER YOU AINT WEARIN NO GLOVES! IMMA CALL YOUR BOSS AND TELL HIM THAT YOU A GROSS MOTHERFUCKER WHO DONT WASH HIS HANDS AND DONT WEAR NO GLOVES!!"
I have a personal policy about customers who cuss at me: I don't serve 'em. It's not Domino's policy, but that is a firm stance I have on that subject. Just because I work a kind of shitty job doesn't mean I have to put up with people putting me down and swearing at me. So I don't do it.
Anyway, after he cussed at me, I walked over to the register, got his money out that he used to pay for the pizza, put it on the counter and said "you have a nice day, now."
He flips his shit. Yelling and screaming and demanding I make his food and make it NOW. I calmly said I had the right to refuse service and was exercising that right. He then says he's going to call the cops. I said "go ahead." He storms out of the store and gets on his cell phone and calls the police.
Cop shows up about 5-10 minutes later, and this guy goes into his story. The cop listened to him outside and then presumably told the guy to wait there and came into the store to speak to me. This is essentially the conversation..
"So this guy said you won't serve him." "Yep that's right." "And you have him his money back?" "Yep that's right." "Well then what the fuck does he want me to do about that??" "Really couldn't tell you officer."
He went back outside and told the guy to beat it, came back in and we had a good laugh about it. He said "This is by far the dumbest thing I've ever had to respond to. Thanks for the entertainment, though." and left.
TL;DR: irate and belligerent customer essentially called the cops on himself thinking the police could force me to serve him.