Any person who shall fail to place and keep stamps denoting the payment of the special tax as provided in section 6806 shall be liable to a penalty (not less than $10) equal to the special tax for which his business rendered him liable, unless such failure is shown to be due to reasonable cause. If such failure to comply with section 6806 is through willful neglect or refusal, then the penalty shall be double the amount above prescribed.
26 U.S. Code § 7273. Penalties for offenses relating to special taxes
1968—Pub. L. 90–618 redesignated former subsec. (a) as existing provisions, struck out heading “General rule”, all references to subsecs. (a) or (b) of section 6806 of this title, provision that nothing in this subsec. affects the liability of any person doing any act, etc., upon which a special tax is imposed for such special tax, and struck out subsec. (b) setting forth penalties for the failure to comply with the provisions of section 6806(c) of this title.