Review sites like Yelp can often help consumers choose a good restaurant and avoid a bad one. But what if the customer comments left there aren't entirely honest -- or have an ulterior motive behind them?

Some restaurants try to ward off bad reviews using a policy of “help us before you Yelp us,” under which they encourage patrons to voice complaints to them personally before letting their fingers fly on social media review sites. But even that doesn't always work.

The Red Rabbit Kitchen and Bar, in Sacramento, CA, recently received a call from a man who said he'd gotten food poisoning there and wanted his tab refunded. Owner Sonny Mayugba said he doesn't issue refunds, but would be happy to send a gift card from any local restaurant the guy chose.

That's when things got really nasty.

“I’ll be doing a scathing review on you on Yelp,” Mayugba said the man told him, “and I’ll report you to the health department. But if you give me a $100 gift card, then I won’t do it.”

The restauranteur ultimately refused to give the man anything, saying he hopes it "inspires other retail establishments and restaurants to push back" against what he calls "flat-out extortion."