As used in this subdivision, "posted" means a sign placed in a reasonable location or locations stating it is a misdemeanor to possess etching cream or a spray can of paint in that public facility, park, playground, swimming pool, beach, or recreational area without valid authorization.
Participation of a parent or guardian is not required under this subdivision if the court deems this participation to be detrimental to the defendant, or if the parent or guardian is a single parent who must care for young children.
Ca. Pen. Code § 594.1