There is also the noise factor. I stumbled across some $60 dollar tanto folder Bodyguards for $3.00 at flea market and snatched them all up. One night in a dark alley three ruffians decided to try and rob me. The locking mechanism was so loud I was sure they had heard it. Fortunately deepening my voice and agressive movement towards them was all that was neccesary to defuse the situation. I alerted a passing officer and they were apprehended a few blocks away. Armed. Attitude can be a deciding factor in preventing trouble.