I think it depends on the situation. If you cant talk your way out and are forced to fight than if you should strike first is subjective. However, the idea of letting them throw the first punch is that your going to let them strike at you, but not let them hit you. There are advantages to letting the other guy strike first. If your ready for it you can use that first punch to lock the guys punching arm and end the fight without having to resprt to beating on someone.