Some pretty decent info on NYS knife laws from KnifeUp online magazine.
“The determination of whether a person intended to use a knife against another may be left up to a jury, and a person still arrested and charged with crime, even though he or she did not intend to use the weapon unlawfully. In People v. Richards, the Court found that because Mr. Richards had not brandished the knife he was carrying, nor had he threatened to use it for any unlawful purpose, but told the arresting officer he had the knife for self-defense, he could not be said to have the intention of unlawfully using the knife. Because self-defense is a justifiable reason to use a weapon, it is therefore not an unlawful one, and Mr. Richards conviction for criminal possession of a weapon was reversed.”
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