So, would you be "on campus" or not? You can't have it both ways: "in front of your child's school " and "on campus after school hours."
California schools generally operate as closed campuses, meaning that anyone who is on campus must be there with the express permission and knowledge of school administration. Any other presence is legally a trespass and you can be removed from the premises and even criminally prosecuted and subject to civil restraining orders and potential civil penalties. Be certain that you have sought and received permission before you set about your plan. It could wind up costing you a lot more than $230.00.
My responses to questions on Avvo are never intended as legal advice and must not be relied upon as legal advice. I give legal advice only in the course of an attorney-client relationship. Exchange of information through Avvo's Questions forum does not establish an attorney-client relationship with me. That relationship is established only by individual consultation and execution of a written agreement for legal services.