No Customs officer or employee shall:
(a) Own, in whole or in part, any vessel except a yacht or other pleasure boat;
(b) Act as agent, attorney, or consignee for the owner or owners of any vessel, or of any cargo or lading on board the vessel; or
(c) Import or be concerned directly or indirectly in the importation of any merchandise for sale into the United States [T.D. 78-394, 43 FR 49787, Oct. 25, 1978]