N.J. Stat. Ann. § 5:2A-24

The provisions of this act shall not apply with respect to a boxing, wrestling, kick boxing or combative sports exhibition, event, performance or contest in which school pupils or instructors are the only participants, except that this exemption shall apply only to a performance or exhibition conducted under the direct supervision and control of the board of education of a school district, or the person in authority of a teachers' training school or other institution under the control of the Commissioner of Education and the State Board of Education, or the boards, bodies, or persons in authority of duly constituted private or parochial schools, colleges or universities, or schools for kick boxing, combative sports, or the martial arts.