ReservationHop and the Orwellian-sounding Food for All, on the other hand, both started out selling reservations without restaurants’ knowledge. Under a hail of complaints (“Everyone seems mad at ReservationHop,” TechCrunch noted last year), the latter stopped operating altogether while the former, following its “soft pivot” to increased coordination with restaurants, made a “hard pivot”—expect to see celebrity couples adopting this phrase to describe their divorces—and abandoned the reservation business entirely.

Killer Rezzy, which operates in New York, is a sort of hybrid. The company is keen to mention its revenue-sharing partnerships with “the best and most sought-after restaurants.” Nonetheless, the site also sells reservations for restaurants without sharing revenue, and sometimes without their cooperation at all. The company’s founder, Sasha Tcherevkoff, is unapologetic: his aim is to keep his customers happy, he says, whether the restaurants approve or not.

And then there’s Shout, an online marketplace like eBay that in principle could be used to traffic pretty much anything, but that in practice appears mostly to involve people selling New York City restaurant reservations to one another.

Outrage about all this has been liberally expressed in Twitter storms and on food blogs, by customers who don’t want to pay for something they feel should be free, and by restaurateurs who object to having their reservations sold without permission or who simply believe the idea lacks class.

But why, exactly, do these reservation traders make us uncomfortable? And what does their existence tell us about what’s being gained and lost in our ongoing march toward a commoditized, peak-priced economy?

These new companies are actually violating two subtly separate traditions. One is the idea that a meal is a meal, and the price should be the same whether it is served at 5 p.m. on a Monday or 8 p.m. on a Friday. The second is that a reservation is part of a meal, not a separate commodity with its own price. The reservation sellers have crossed both lines, treading on the pristine sanctity of restaurant customs.

Let’s first consider the idea that reservations should not be bought and sold. It’s true that certain things change when they involve a financial transaction. It would be odd to pay your mother-in-law for Thanksgiving dinner. The most casual of one-night stands is regarded as qualitatively different from paying for sex with a professional. The gift of a kidney seems noble; the sale of a kidney, not so much.

Perhaps all of this is what Tina Vaughn, a Manhattan restaurateur, had in mind when she criticized reservation sales in a New York Times article last year that was headlined “Hospitality Has No Price.” But I’m sure that if I were to dine at Vaughn’s restaurant, the Simone, she would be unimpressed if I left without paying on the basis that “the pan-roasted black sea bass has no price.” The meal is a market commodity, so why claim that the reservation is something altogether different?