Family locked in restaurant for not tipping?

A Houston family says they were locked inside a restaurant and had the police called on them when they refused to pay the tip. The restaurant had added an automatic 17% gratuity because the family had more than five people in their party (a policy that’s stated on their menu) but the family says the service was bad.

The restaurant's on-duty manager told KPRC that they don't usually have issues with people tipping, but admitted they've had to call the police before over the same issue.

Have you ever been out to a restaurant where the service was terrible? What did you do when you got the bill?