im 15 and ive been carrying a knife since i was 11. first of all, it is a fantastic tool to have. very handy in tons of situations. second, nobody is going to give a damn if you carry a knife around. cops stop me all the time and as long as its not a switch, then they shouldnt care. which brings me to my next point. i have a legitimate switchblade that i carry only for self defense(because im young, you never know) and when i know the popo aren't gunna roll up and search me. if you carry a regular folding knife with a lock and such then it shouldnt open in your pocket,or at least none of mine have. just use your brain about how to ue it. its pretty much common sense.