Cal. Bus. & Prof. Code § 25608
(a) Every person who possesses, consumes, sells, gives, or delivers to another person an alcoholic beverage in or on a public schoolhouse or the grounds of the schoolhouse, is guilty of a misdemeanor. This section does not, however, make it unlawful for a person to acquire, possess, or use an alcoholic beverage in or on a public schoolhouse, or on the grounds of the schoolhouse, if any of the following applies: