I'm not so sure that it does. It relies on filling the tables at the restaurants. The restaurants don't care if the people who come to fill your table aren't the same ones that originally booked the reservation. Nor do they care if a certain number of reservations are no-shows, if the number of no-shows is smaller than the number of people waiting at the door.
Restaurants are in the business of filling their tables by making customers happy -- those customers will return, tell their friends, and the tables stay full. By filling up available spaces (thus resulting in customers being told that a very long wait is to be expected) and providing a paid line-cut (who enjoys being cut in front of while waiting 60 minutes?), you're going to make a lot of the restaurant customers unhappy, both directly and indirectly.
If this was an ethical business, they would have told the restaurant what they were doing and received approval before they decided to lie to the restaurant to achieve their aims.
Restaurants are in the business of filling their tables by making customers happy -- those customers will return, tell their friends, and the tables stay full. By filling up available spaces (thus resulting in customers being told that a very long wait is to be expected) and providing a paid line-cut (who enjoys being cut in front of while waiting 60 minutes?), you're going to make a lot of the restaurant customers unhappy, both directly and indirectly.
If this was an ethical business, they would have told the restaurant what they were doing and received approval before they decided to lie to the restaurant to achieve their aims.