The term "tips" is an acronym of the phrase "to ensure prompt service." Tipping a restaurant employee is not legally considered mandatory, but it is considered polite in many places, including the United States. Generally, diners will be left to calculate their own tips. A tip on a meal between 15 percent and 20 percent is considered polite. However, some restaurants assess "mandatory" tips on meals.
According to the "New York Times," a tip is not legally enforceable, even if the restaurant declares it mandatory. In 2004, a New York restaurant patron refused to pay a mandatory 18 percent gratuity on a bill and was arrested for theft of services. However, the judge found him not guilty, stating that the payment of a tip is not legally enforceable by a restaurant.
While a restaurant cannot technically mandate the payment of a tip, this does not mean that the restaurant cannot charge another fee that resembles a tip but is given another name. For example, a restaurant can charge an 18 percent "seating fee" or "service charge" on large parties. This money is not technically considered a tip and is therefore legally enforceable. However, it must be announced before the party begins its meal.
While a tip may not be legally enforceable, a local police force -- or a local judge -- may see the matter differently. This means that even if a restaurant patron declares to the restaurant that it does not legally have to pay the mandatory tip, police may still be summoned and the person may still be arrested. Whether a restaurant will choose to press charges, however, is up to the restaurant.