Well, as an example I keep a M3CB on my duty belt for work. Would I use the CB for defense? Most likely I would not have to, but if it were a last resort, or it was the only "tool" in my hand at the time I would say it could be useful. I believe, b/c of experience, that light is a good form of defense. Why do you think when you get pulled over at night there are a number of bright lights raining down on your vehicle from the patrol car? This light not only can conceal your position, but give you a tactical advantage. I use my flashlights on a regular basis to my advantage when I am questioning individuals. A quick flash, or constant on of a nice bright beam gives me an advantage, and generally takes away a persons ideas of advancing on what they can't see well. Of course this is something that should be done with training, and not in a situation that would put you in harms way.