Support BladeForums! Paid memberships don't see ads! I don't know of any state or city where using a knife to commit a crime would not be illegal. In AZ any knife is legal, concealed or not. Yet, right next door in New Mexico, technically any knife carried concealed is illegal. But in almost 30 years in NM law enforcement I never knew of anyone charged with carrying a knife as a "concealed deadly weapon" even they did use it. Charged with the assault, yes, charged with carrying concealed, No.