Economically, it’s a no-brainer. European data show that the scanners actually increase tips by 9 percent, because preset tip buttons ensure that servers aren’t shorted by sloppy math. Pay-at-table technology also saves time by eliminating extra trips to the register. Another benefit of scanners: they reduce the risk of identity theft. “The restaurant business is one of the only industries left where a person takes your credit card and disappears,” says Roger Berkowitz, president of Legal Sea Foods. There is a lingering etiquette issue, though: when do you tip? In Europe, service is included. But here, deciding on a gratuity while a waiter hovers nearby to take back the scanner could make customers feel rushed. “The key is, no awkward moment,” says Grant Drummond, marketing communications director for Toronto-based Ingenico, a leading manufacturer of wireless-pay technology. “Servers should give a little spiel about how the device works, and then walk away.” If only those machines could pick up the tab, too.