26 U.S.C. § 6717

(a) In general In addition to any other penalty provided by law, any person who refuses to admit entry or refuses to permit any other action by the Secretary authorized by section 4083(d)(1) shall pay a penalty of $1,000 for such refusal. (b) Joint and several liability (1) In general If a penalty is imposed under this section on any business entity, each officer, employee, or agent of such entity or other contracting party who willfully participated in any act giving rise to such penalty shall be jointly and severally liable with such entity for such penalty. (2) Affiliated groups If a business entity described in paragraph (1) is part of an affiliated group (as defined in section 1504(a)), the parent corporation of such entity shall be jointly and severally liable with such entity for the penalty imposed under this section. (c) Reasonable cause exception No penalty shall be imposed under this section with respect to any failure if it is shown that such failure is due to reasonable cause.