From the NC law:
(d) Sending or assisting a person 18 years to purchase or receive tobacco product.products or cigarette wrapping papers. - If any person shall send a person less than 18 years of age to purchase, acquire, receive, or attempt to purchase, acquire, or receive tobacco products or cigarette wrapping papers, or if any person shall aid or abet a person who is less than 18 years of age in purchasing, acquiring, or receiving or attempting to purchase, acquire, or receive tobacco products or cigarette wrapping papers, the person shall be guilty of a Class 2 misdemeanor; provided, however, persons under the age of 18 may be enlisted by police or local sheriffs' departments to test compliance if the testing is under the direct supervision of that law enforcement department and written parental consent is provided; provided further, that the Department of Health and Human Services shall have the authority, pursuant to a written plan prepared by the Secretary of Health and Human Services, to use persons under 18 years of age in annual, random, unannounced inspections, provided that prior written parental consent is given for the involvement of these persons and that the inspections are conducted for the sole purpose of preparing a scientifically and methodologically valid statistical study of the extent of success the State has achieved in reducing the availability of tobacco products to persons under the age of 18, and preparing any report to the extent required by section 1926 of the federal Public Health Service Act (42 USC § 300x-26).