Counties, cities and counties, and cities may provide for the calling of test exercises, either singularly or jointly, whenever, in the opinion of such political subdivisions, such test exercises are needed; provided, however, that with respect to any such test exercise no one shall have the power to command the assistance of any private citizen, and the failure of a citizen to obey any order or regulation pertaining to a test exercise shall not constitute a violation of any law.
Ca. Gov. Code § 8611