Mack Darin owns and operates a store in a rough downtown neighbourhood. Last week, he received a shipment of switchblade knives. He placed one of the knives in his store window, alongside a small notice board that said, “Switchblade Knives—$25 each.” That display soon caught the attention of Constable Boot, a member of the local police department. Darin was arrested and charged with a crime under section 7 of the Prohibited Weapons Act, which says that it is illegal to “manufacture, sell, rent, or offer for sale or rent. . . any knife. . . which has a blade that opens automatically by hand pressure applied to a button, spring, or other device in or attached to the handle of the knife.” There is no doubt that the switchblade that appeared in Darin’s store window falls within that description. Is it therefore safe to assume that Mack Darin has committed a crime? Explain your answer.