I think you might be giving servers too little credit - they will know exactly why you have not tipped, I wouldn't sit there nodding politely throughout the meal, I would have said something to them long before it got that far. I know a friend of mine who will write "0 - bad service" on the tip line of a credit card slip, but I will have said something long before then to the server. Some just don't give a moneky's and frankly, I am not about to reward that, even with a dollar.

I was in the industry in the UK - where pretty much every server and bartender makes far less total than their America counterparts. Bar tender and assistant restaurant manager were my two main industry positions but I also waited tables, cooked in the restaurant, and other assorted dogsbody jobs!