N.C. Gen. Stat. § 119-1: Unlawful substitution.

It shall be unlawful for any person, firm or corporation to fill any order for lubricating oil, designated by a trademark or distinctive trade name for an automobile or other internal combustion engine with a spurious or substitute oil unless and until it is explained to the person giving the order that the oil offered is not the oil that he has ordered, and the purchaser shall thereupon elect to take the substitute article that is being offered to him. (1927, c. 174, s. 1.)