If you declare that you are “doing business” or somehow connected to “business” in NC (or probably anywhere in the USA, you are volunteering your activities to be treated as privileged:
§ 105-114. Nature of taxes; definitions.
(a) Nature of Taxes. – The taxes levied in this Article upon persons and partnerships are for the privilege of engaging in business or doing the act named.
(3) Doing business. – Each and every act, power, or privilege exercised or enjoyed in this State, as an incident to, or by virtue of the powers and privileges granted by the laws of this State.“