[MarchHare]

And the real choice quote is this one:

Here’s the underlying math of the whole thing. Let’s take a typical, Linkery-like restaurant (but one that accepts tips) where the guest spend average is about $25/pp, and our server can count on serving 40 guests in her five-table section on a busy weekend night.

At 21% average tip, her base level of tips is $210 before tipout

If she is able to increase her quality of service to top-tier, and things also go well with the parts of service she can’t control like the kitchen’s work, she would likely increase her average tip to 23%. Now she has increased her tips by $20, to $230 before tipout. She’s pretty dependent on the kitchen for this to work though, so she’ll probably tip out more to them in this case. I’ll estimate she ends up with a raise of $15 for the night.

If the server instead focuses on using the “Mega-Tips” techniques — such as calling the guests by name, touching them on the shoulder, squatting to meet the guests at eye level, and drawing smiley-faces on the check, all things which don’t require assistance from the kitchen — she’ll probably increase her tip average to 23% (or more) as well. In this case she’s less likely to increase her tipout to the kitchen, so she’s really increased her income by a full $20 for the night.

If she focuses on increasing sales to her section, she might get her guest spend average up from $25 to $28 — a very big increase from the business’ point of view. This, at 21% tip, would get her to $235, a raise of $22 from her original base.

Lastly, if she instead focuses her attention on increasing her section size — something which can be done in many ways, from coaxing/bullying the host or swooping in on tables, to emphasizing to the shift manager that it would save labor costs, or even telling a manager that the server next to them is overloaded and should cede some of his section — our server could bump her section from five, to say, eight tables, increasing the number of guests she serves in a night from 40 to 64. If she maximizes her section size, this will at some point stretch her to a point where her guests start getting poor service and are unable to purchase as much as they want. Let’s that happens here: sales per guest drops to $22 (a huge drop from the business’ point of view), tip percentage drops to 19%, and guests are less excited to return. This is a nightmare scenario for the business, and also lousy for the guests, but our server’s income before tip out has risen to $268, by far her highest yet. By pushing number of guests to the maximum possible, she’s made a raise of $58 on the night.

You can play with the numbers and scenarios to get slightly different results. But in general, in most restaurants, increasing the number of guests served is the surest way for a server to increase her income — even if the quality of service decreases markedly. This is because people don’t actually decrease their tip much for lousy service; and that total decrease is not nearly as much as the increase in total tip revenue gained by the server squeezing in some extra guests.

This is the plainest mathematical explanation I can give you to show that the tipping system, which is believed by customers to maximize quality of service, and believed by many restauranteurs to minimize the amount of supervision required of servers, actually works against the interests of both the guests and the business.

Emphasis added.