[lazaroclapp]

How about doing it the other way around? The restaurant includes a fixed percentage charge for the service on all items, announces it prominently, requites waiters to refuse any additional tips.

One can argue that, because the advertised prices would be, say, 18% higher, the restaurant would fail due to customers preferring restaurants with lower advertised prices. But at least the experiment could be run in this case in a more or less ethical manner (costs to the business itself could be absorbed by a speculative insurer that is convinced business will not decrease for that particular restaurant). Might not even matter for really high end restaurants, since they don't advertise prices anyways.

[jnbiche]

Yes, that would be ethical, I believe. In fact, in many restaurants, this is how things are now for tables of 6 or more.