I've always maintained it should be legal for everyone to carry around a full daisho. If everyone had two swords strapped to their belt at all times and knew how to draw them at insane speeds, I'm sure violent crimes would diminish significantly.

Seriously though, I don't carry anything on my person. I have considered carrying a knife, but really, I am not sure I want to engage someone in a knife fight, if I am overpowered the likelihood of my getting killed increases dramatically.