Every application for a license under this section must be duly verified and in writing, and, in the case of a corporation or association, signed by its president and attested by its secretary. It shall set forth the information required by the commission and the application for a participant's license must be accompanied by a copy of the applicant's birth certificate or other proof of age as may be acceptable to the commission and a written waiver by the applicant of any cause of action against any member or employee of the commission, or of any county athletic commission, referee, ringside physician, or other official arising out of the proper performance of their official duties. No license may be granted to a participant less than eighteen years of age but the commission may by unanimous vote waive this age limit for a specific participant. License applications must be filed with the commission at least one week prior to the commission's actions but the time requirement may be waived in the event of emergency substitutions.