Cal. Lab. Code § 4907

(a) The privilege of any person, except attorneys admitted to practice in the Supreme Court of the state, to appear in any proceeding as a representative of any party before the appeals board, or any of its workers’ compensation administrative law judges, may, after a hearing, be removed, denied, or suspended by the appeals board for either of the following: (1) For a violation of this chapter, the Rules of the Workers’ Compensation Appeals Board, or the Rules of the Administrative Director. (2) For other good cause, including, but not limited to, failure to pay final order of sanctions, attorney’s fees, or costs issued under Section 5813.