In Banales v. Municipal Court (1982) 132 Cal.App.3d 67, a group of striking workers trespassed to communicate with the strike breaking farm workers. The issue was "the jurisdiction of a state court over conduct which is arguably protected by the Agricultural Labor Relations Act (hereafter ALRA)." (Id. at p. 70.) Because it was well established in California that peaceful labor activity, including trespass on to private property, was conduct protected by the ALRA, the National Labor Relations Board preempted the trial court's jurisdiction over the defendants' criminal prosecution. (Banales, at p. 73.)