From what is stated in the article, the restaurant may not be blameless, no matter what is printed on the menu, or how prominently. If the bill, as presented, had an 18% charge, precalculated and labeled [e.g. “Service charge for parties of 6 or more” ], and a calculated total, then the patron might be expected to question the charge, rather than disregard it. If (as is often the case) the servers don’t clearly specify the mandated tip (in the hope of getting more), then expecting a patron to notice and include the expected minimum is much less reasonable.
A bill isn’t the full substance of a contract, but any business must clearly specify what they consider “payment in full for services rendered”, and a bill -though negotiable- is a business’ offer of final settlement. The ‘debt’ must end somewhere. Imagine if any other business tried to dun you or have you arrested for a fee they expected you to pay but never billed you for.
A tip is a sort of “delivery and installation charge”. If a company delivers/installs a refrigerator without explicitly telling you about, or billing you for, their “large appliance charge”, and you pay in full, they’ll be on shaky ground if they try to later claim that charge, no matter what is posted at the store. The deal was concluded on terms they spelled out in dollars and cents, as surely as if you’d negotiated with the manager to have the charge waived.
The patron said he didn’t notice the wording on the menu, but didn’t mention if the charge was on the bill. If it was, and he disregarded it as a ‘suggestion’, a court may reasonably expect hime to contest it before payment, rather than recalculating the bill on his own terms, and unilaterally leaving his own version of “payment in full” (You certainly can’t do that most bills!) If the restaurant didn’t bill him for the service charge, their case is very weak, no matter what is on the menu. It’s not my job to seek out and obey internal company policy; it’s their job to bill me.
Thel “leave payment and go” method at most restaurants is convenient, but it leaves room for unfulfilled expectations, which build up and create an often tense subculture. Based on discussions with servers and ex-servers, it seems that they they don’t fully credit patron dissatisfaction; it seems a different category to them. Sure, we are all sometimes disappointed by our purchases, but that’s a problem that shouldn’t be accepted as “fact of life”.
Servers hope for more money when a customer raves about a meal they didn’t cook, but don’t like being penalized for a meal they didn’t botch. I’ve always felt that the system puts an unfair burden on them, and the patron, in many ways.