moonfirespamGoes for practically in your possession (or constructive possession) while you're near cops. Hell, if a cop sees you waving a pen around admonishingly during a lively discussion they might confiscate it as a weapon to make sure it's not a magic wand you're using to practice the dark arts ;)
moonfirespamAs long as it is in clear sight its okay. If they ask to search you or your bag and find it on you without you immediately telling them you have it on your person they will absolutely take it. Otherwise you're pretty safe off carrying a knife that is not illegal in anyway