My sensei, from day one taught us that the best way to avoid a punch is not to be there. This does not only mean to duck, move out of the way, or run away from an altercation, but it means not to get yourself into a situation that requires you to have to defend yourself.
But I am also a realist. I did answer probably yes to this question. I understand that you cannot avoid every situation, and someday you may be put to the test. I know that if I ever get into one of these situations where I can't avoid, I do know that no matter what, I am going to be going home to my wife and kids, whatever I have to do. I do not enjoy hurting other people, but I love my family more and I plan to be around for a long time.