In what circumstances will a court strike down an ordinance that prohibits off-site advertising?

For the reasons we shall offer, however, we believe that this doctrine, too, conflicts with reality and with current views of the police power. The distinction between prohibition and regulation in this case is one of words and not substance. "(E)very regulation necessarily speaks as a [26 Cal.3d 864] prohibition." (Goldblatt v. Hempstead (1962) 369 U.S. 590, 592, 82 S.Ct. 987, 989, 8 L.Ed.2d 130.) In the present case, for example, plaintiffs describe the ordinance as a prohibition of off-site advertising, while the city describes it as a regulation of advertising, one which limits advertising to on-site signs. Surely the validity of the ordinance does not depend on the court's choice between such verbal formulas.