I would agree that one might not know the portion size before going to a restaurant, but often people expect to get mountains of food, no matter what price is paid. Having been in the restaurant business in a former life, you would be surprised to know that people DO complain about the price. Often I adjusted their checks as a courtesy and for goodwill, but many people do equate restauarant quality with portion size, without considering the quality of the products being used and the expertise of the executive chef in creating the menu and food preparation.