Cal. GOV § 6650

(a) Any marching band organized by or maintained by any educational institution supported in whole or in part by public funds or granted any tax exemption as an educational institution may furnish music at any athletic event where an admission is charged by any private person, partnership operating for profit, or corporation organized for profit only under the following conditions:

(1) The performance is authorized by the governing body of the institution;

(2) A band or orchestra of not less than the number of professional musicians customarily engaged for the athletic event in the particular auditorium, stadium, or place of performance or 15 professional union musicians, whichever is greater, is employed to furnish music at the event; and

(3) Neither the person, partnership, or corporation, nor the agent thereof, advertises or makes known to the public by any means or through any medium the pending performance of such marching band as an added attraction to the event itself; provided, however, that any person by any means or through any medium including radio or television may identify such marching band to the public at the actual moment of performance or thereafter.

(b) Any band or orchestra organized by or maintained by any institution supported in whole or in part by public funds or granted any tax exemption as an educational institution may furnish music at any activity of any other such institution when authorized by its governing board.

It is the intention of the Legislature to encourage the musicianship of California’s student bandsmen in marching bands but in no way to reduce employment opportunities for professional musicians. Private employers of professional musicians are to be advised that the Legislature intends to encourage such employers to invite California’s student marching bands to perform but not to regard such specialized marching performances as providing a substitute for the performance of regularly employed professional musicians which would ordinarily be required by such employers for such admission-paid events, in the absence of any performance at the same event by a student marching band.