Yeah, doing that stealthily ought to be illegal - and in some places it is. In NYC, mandatory or automatic service charges have to be conspicuously disclosed to

Yeah, doing that stealthily ought to be illegal - and in some places it is. In NYC, mandatory or automatic service charges have to be conspicuously disclosed to consumers before food is ordered, by law. Conspicuously is interpreted accurately enough that merely hiding it on the back of the menu isn’t enough, let alone not disclosing it until the bill at the end of the meal. And most other restaurant-imposed surcharges on top of listed food and beverage prices, which aren’t bona fide service charges, are categorically forbidden. A mandatory blanket extra percentage that isn’t a bona fide charge for some service, like handling a large party or splitting a bill, is likely illegal in NYC even when labeled as a service charge, although not as rare as it should be. (Taxes can still be added on separately.) Sadly for the rest of the state and country, these requirements are just local rules and regulations, not state or federal. But some other places do have similar laws.