Well, I guess this explains why I don't get bothered much. First, down here I look like Herman Munster - secondly, Gringos are known for being nuts (just look at our movies). No mugger wants to take on someone who can do serious damage unless they are desperate.
One other thing - the best Self-defense is an attitude. I spent more than my share of time in bad sections of towns. Never was bothered (but in school, till I learned, boy did I have the fights!) I looked like I really wouldn't mind the fight... and I wouldn't be nice in it.
If someone knows you aren't going to be civilized - well, it tends to make them think twice. After all, for most of us, we are in a LOT better shape than they are.
Of course my real solution was to move to a place where people are peaceful. Unless someone is drunk - they just don't fight much down here. All I fight down here is chickens and cows.