You can have your cake and eat it too (if you were a Roman restaurateur)

There is an economic model that predicts that a restaurateur will choose to serve low-quality food when many of his customers are tourists. The intuition is this. The restaurateur would like to sell the high-margin, low-quality food as long as he doesn’t risk losing future business. This strategy is sound in areas with heavy tourist-traffic because tourists tend to be one-time customers. The downside to this strategy, of course, is that the locals know the restaurant serves lousy food and will not eat there. Now, if there were only a way to get both those tourists and those local customers…

Diner Beware: Turisti Pay More in Roman Restaurants
By PETER KIEFER
NY Times

ROME, Aug. 8 — Any tourist here knows the sensation: that gnawing feeling that Italians do not pay $3 for a tiny cappuccino or $4 for an unordered basket of bread.

To no one’s surprise the suspicion often reflects reality, as restaurateurs will admit in candid moments. It might be an extra 30 cents for an espresso, or a $5 tithe tacked onto a bottle of wine. It may even mean the substitution of lower grade ingredients...

Fuzzy math on an unitemized receipt, an inflated bread and cover charge, pricing discrepancies between the English menu and the Italian one or even that stupefying, disproportionate service charge for taking your coffee seated at a table instead of standing at the bar.
If it is not your wallet that is suffering, it may be your palate...

This is how the racket works: an unscrupulous waiter will flag an order of say, pasta carbonara or amatriciana, as having come from a foreigner and not a proper Roman. It is then up to the kitchen to proceed with whatever cost-cutting tricks it deems necessary. That can include anything from diluting the sauce to using precooked pasta to substituting lower grade or even day-old ingredients for the appropriate ones. “If the menu outside says it is seven euros for a plate of pasta carbonara — then it’s seven euros for everyone,” he said. “But if you try and give a real Roman the low-quality version they will throw it back in your face...” (my emphasis)