(a) The penalties for violation of ex parte communication rules specified in this section are applicable only to:

(1) Nature of postal service proceedings conducted pursuant to 39 U.S.C. 3661(c);

(2) Appeal of Postal Service decisions to close or consolidate any post office conducted pursuant to 39 U.S.C. 404(d)(5); and

(3) Rate or service complaints conducted pursuant to 39 U.S.C. 3662.

(b) Upon notice of a communication knowingly made or knowingly caused to be made by a participant in violation of § 3012.5(a), the Commission or presiding officer may, to the extent consistent with the interests of justice and the policy of the underlying statutes, require the participant to show cause why the participant's claim or interest in the proceeding should not be dismissed, denied, disregarded, or otherwise adversely affected on account of such violation.

(c) The Commission may, to the extent consistent with the interests of justice and the policy of the underlying statutes administered by the Commission, consider a violation of § 3012.5(a) sufficient grounds for a decision adverse to a party who has knowingly committed such violation or knowingly caused such violation to occur.