The following are exempt from this chapter while engaged in the proper discharge of their professional duties:
(1) a manufacturer's representative or sales person who demonstrates a product or technique for a promotional purpose;
(2) an educational activity conducted in connection with a monthly, annual, or other special program from which the general public is excluded, provided this exemption applies only to the specific days of the special program;
(3) a demonstration conducted by a manufacturer or a wholesaler for the purpose of exhibiting the technical application and use of a product; and
(4) an unlicensed person employed in a cosmetology salon whose duties are expressly confined to shampooing hair under the direct supervision of a cosmetologist.