California Code, Business and Professions Code - BPC § 18888.4

(a) A promoter may, but is not required to, add to the price of each ticket sold for a professional mixed martial arts contest an amount specifically designated on the ticket for contribution or as a donation, either or both, to the MMA Fund.  The additional amount shall not be subject to the admissions tax required by Section 18824 or any other deductions.  This subdivision does not authorize the addition of those amounts to less than all the tickets sold for the professional mixed martial arts contest involved.  The promoter shall pay additional contributions collected in accordance with Section 18888.2.

(b) Any additional contributions received pursuant to this section shall not be considered to offset any of the contributions required by the commission under Section 18888.2.