Methinks some folks have never used a knife in their life, apart from maybe buttering their toast, if they think this is a sound thing to do. Like all tools, most are used in good hands by good people for good purposes, but hey… one person fucks it up and that’s enough to take it away from everyone, right? (let’s ban cars then for that matter). Knives are even more handy than guns, as I think most people tend to go through their day cutting at least one thing (food, especially). My Leatherman is quite a handy tool, and the ability to open the blades one-handed is an important feature. If you’re a person that does work with your hands, very often you need to hold, stabilize something with one hand then cut with the other… you must have a folding knife you can open with one hand.