One of the most frustrating things about tennis is line calling. I try to be as accurate as possible. But some of my playing partners are very different. One mixed doubles team I've played against is very generous with line calls, to the point that I'm sometimes embarrassed if we win a set off them. They'll return serves when the ball from my vantage point appears to be 2 or 3 inches out. Another guy is a relentless cheat. He'll cheat on every line call possible. This infuriates me but no one else seems to mind one bit. They never question him. Question: 1. do I have to be equally generous with line calls when the other team is? It seems the proper etiquette. 2. what's a graceful way of dealing with line cheats?