Let me add one more thing... I worked in some basic restaurants (American Cafe, Houlihan's) and some higher end restaurants with complex wine lists. There is a difference. In the higher end restaurants, waitstaff was supposed to be educated on the wine and wine service. We needed to be able to answer questions and guide customers to the best wine for the meal. There was education, with wine salespeople and experts coming in regularly to teach. If you are ordering a $400 bottle of wine, you are likely working with an educated, skilled server who deserves higher compensation for that skill. There seems to be a misbelief that some guy off the street is selling high end wine, which, of course the restaurant would not do. Waiters are the restaurant's sales staff, so a restaurant would be missing sales opportunities if it allowed untrained staff on the sales floor.

It's like the difference between getting your hair cut at SuperCuts versus Pierre Michel Salon in midtown Manhattan, where if you left a $5 tip you'd never be able to get another appointment. You walk in the door expecting different levels of training and execution and know you are going to pay more for the Pierre Michel skills.