The rationing already occurs in the reservation process, without money changing hands.
> This is by definition increasing economic efficiency
Bespoke markets are by definition economically inefficient. There's a reason most people buy mass-manufactured cars, and it's not just the cost, it's that bespoke car production cannot make enough cars to meet demand.
At absolute best a bespoke market may sell a few more of a limited set of dining opportunities to others through the additional marketing medium. At better what bespoke markets do is maximize profit taking. At bad this maximization of profit taking channels money to the middleman that otherwise would have gone to the merchant (as there will be people who pay for a reservation and then order the cheapest meal at the restaurant, as they can't afford more). And at worst this makes it inconvenient for people to frequent the restaurant, resulting in an overall reduction of customers. The bad and worst circumstances can result in fewer operating restaurants. And artificial resource scarcity is the opposite of economically efficient.
If scalpers (who have overheads of their own) are making money then that implies the restaurant is doing the economic equivalent of leaving a lot of $100 bills on the floor. Before those bills were being picked up by random customers but now they are being picked up by people who heard there were restaurants leaving $100 bills on the floor. But the cause is ultimately the restaurant choosing to just give up free money by not charging a price so that supply and demand equal and the market clears.
You're assuming my "bad" and "worst" scenarios do not exist. And also assuming that knock-on effects don't occur which cause issues in other parts of the economy. A cartoon-like example: spend X+Y money to dine at restaurant, spend -Y less money elsewhere, people working elsewhere are laid off and can no longer afford to spend money at restaurant. Restaurant loses customers. Restaurant closes.
Mutually assured destruction does happen. The problem is if there are more potential scalpers who are convinced they know why the previous scalper failed than there are restaurants that can absorb the hit.
> This is by definition increasing economic efficiency
Bespoke markets are by definition economically inefficient. There's a reason most people buy mass-manufactured cars, and it's not just the cost, it's that bespoke car production cannot make enough cars to meet demand.
At absolute best a bespoke market may sell a few more of a limited set of dining opportunities to others through the additional marketing medium. At better what bespoke markets do is maximize profit taking. At bad this maximization of profit taking channels money to the middleman that otherwise would have gone to the merchant (as there will be people who pay for a reservation and then order the cheapest meal at the restaurant, as they can't afford more). And at worst this makes it inconvenient for people to frequent the restaurant, resulting in an overall reduction of customers. The bad and worst circumstances can result in fewer operating restaurants. And artificial resource scarcity is the opposite of economically efficient.