One time My entire family was at a buffet style brunch for Mothers day. We helped ourselves to the buffet. The only work any of the waitresses had to do was clear our plates. Well when the bill came there was a 20% gratuity added to the bill. Long story short we fought the owner ( verbally ) he threatened to call the police and we told him to do so but he never did. We did not pay their mandatory tip and never went back in that restaurant again. My feeling on the situation was the owner should have been paying his waitresses a larger salary that day. They did not wait on us or perform any duty for us. The restaurant business gets away with low salary's because of tipping.