The following persons shall not be required to register under the provisions of § 34-20B-29:
(1) An agent, or an employee thereof, of any manufacturer, distributor, or dispenser of any controlled drug or substance if such agent is acting in the usual course of his business or employment;
(2) A common or contract carrier or warehouseman, or an employee thereof, whose possession of any controlled drug or substance is in the usual course of his business or employment;
(3) A person in possession of any controlled drug or substance pursuant to a lawful order of a practitioner.