Legal Question in Business Law in California

"Business rules" may fall into one or more of several categories, most of which don't need to be posted. For example, restaurants don't have to post signs saying "pay when served" nor "pay before departure." Signs regarding smoking real cigarettes don't have to be posted; that requirement is fixed by law. Signs saying "African-Americans Not Served" cannot be posted because selecting customers based on race is contrary to Federal law. I'd conclude that businesses are not required to post signs advising clientele of each and every law or rule applicable to them. That would require so many signs there's be no room for merchandise. The law does require posting certain items (local business license, perhaps, or restaurant inspection signs in some jurisdictions), fire escape signs, etc., but not for every law, rule or policy that may affect customers.