Ed. Code, § 44810

(a) Every minor over 16 years of age or adult who is not a pupil of the school, including but not limited to any such minor or adult who is the parent or guardian of a pupil of the school, who comes upon any school ground or into any schoolhouse and there willfully interferes with the discipline, good order, lawful conduct, or administration of any school class or activity of the school, with the intent to disrupt, obstruct, or to inflict damage to property or bodily injury upon any person, is guilty of a misdemeanor.

(b) A violation of subdivision (a) shall be punished as follows:

(1) Upon the first conviction, by a fine of not less than five hundred dollars ($500) and not more than one thousand dollars ($1,000), or by imprisonment in a county jail for not more than one year, or by both the fine and imprisonment.

(2) Upon a second conviction, by imprisonment in a county jail for a period of not less than 10 days, and not more than one year, or by both imprisonment and a fine not exceeding one thousand dollars ($1,000). The defendant shall not be released on probation, or for any other basis until he or she has served not less than 10 days in a county jail.

(3) Upon a third or subsequent conviction, by imprisonment in a county jail for a period of not less than 90 days, and not more than one year, or by both imprisonment and a fine not exceeding one thousand dollars ($1,000). The defendant shall not be released on probation, or for any other basis until he or she has served not less than 90 days in a county jail.

(4) Upon a showing of good cause, the court may find that for any mandatory minimum imprisonment specified by paragraph (2) or (3) of this subdivision, the imprisonment shall not be imposed, and the court may grant probation, or the suspension of the execution or imposition of the sentence.