I can't help but weigh in, even though everybody already said it. You seem to have a major misunderstanding about etiquette and the way a restaurant works. A waiter is a person, not a slave. There is nothing wrong about asking you for the tip since that is a server's salary, just like you would ask for your paycheck at work if they mysteriously didn't give it to you. Yes, if the service is horrible you can leave a small tip, but to not leave tips on a regular basis because you are low on money is utter rudeness and there's nothing wrong with another human being pointing it out, even twice. It doesn't matter if you aren't the one paying either - when I am treated to dinner by a cheapskate who doesn't leave enough, I add something myself to the tip so the waiter can get paid. Sorry, but tips in restaurants are obligatory in this country, not optional.