It's actually a common headache with some of the weapon laws that allow possession and use as a collector or as historical reenactment, etc. My personal take, as a cop, was simple: The guy with "nunchuks" concealed in his pants leg... he's charged. The guy with them "concealed" in his training bag, with a uniform and other martial arts gear? He's taking them to or from a training facility. They guy practicing with them in a park, doing a kata or practicing drills? Training. The guy using them to whack street signs or just flailing at stuff? Not training.