The economics of trust

The current edition of Restaurant Magazine has an article on a restaurant in the suburbs of London where there are no prices on the menu. Customers pay what they think the meal was worth. It is called Just Around the Corner and has been around for 17 years. From what I saw when I went to help photograph it for the magazine, it serves old fashioned French food of an average standard (soup, chicken supreme, profiteroles...).

Here are some interesting quotes from the owner:
In a cheaper area the restaurant wouldn't survive because people wouldn't pay the money I expect and in a busier, more central area, we couldn't build up the trust.

When people don't pay what the owner thinks appropriate (about £20 a head) We just thank them nicely and give them their money back. These people know they don't belong here, they try you out and by giving them their money back nicely, you ensure that they never return.

Apparently this is a unique operation and as the owner admits, location is key. But I think there is more to the location than simply wealth, as the owner states. If there were more competition (there isn't a great deal nearby), would it survive? Why hasn't the approach been imitated, as it is obviously profitable?
The owner is very charismatic, and the restaurant has what some would call a nice atmosphere, so perhaps it has become a local institution which survives due to a combination of scarce competition, a gastronomically conservative clientele and a charming and familiar atmosphere. The absence of competition is important because a comparable local restaurant would enable people to price a meal at Just Around the Corner more accurately, acting as a kind of yardstick.

Even if a customer was unhappy with the food, there would probably be a shame factor, helped by the kindness of the owner, which induced him to pay a "reasonable" price, even if he never returns again.

I would be interested if anyone knows of similar operations around the world, especially any that have failed with a similar business plan.