First Amendment Coalition legal director David Loy told The Washington Post that the court's decision "punishes a very common and ordinary form of political expression that people engage in every day."

"I was shocked that [California] law prohibits a common and widespread means of political, social, and personal expression," Loy said in a February interview on his group's website. "The government should not be stifling a critical form of expression, especially when public-health restrictions can curtail other means of assembly and protest, as we've sometimes seen during the COVID-19 pandemic. The statute at issue, Cal. Vehicle Code § 27001, allows horn use to give a warning but prohibits it to communicate any other message. As applied to expressive horn use, that is the essence of unconstitutional content-based discrimination."

California isn't alone in restricting expressive honking. Court rulings on these laws have been mixed, as Belmont law professor David L. Hudson, Jr. points out.

In a 1998 case, the Montana Supreme Court said protest-oriented honking "did not constitute a protest to government of government acts which would be entitled to protection under the First Amendment." A federal court in New York has also rejected the idea that horn honking is protected expressive conduct.

"However, at least one lower court has recognized a free expression challenge to a horn-honking law, albeit on state constitutional law grounds," Hudson notes. "The Oregon Court of Appeals, in City of Eugene v. Powlowski (Ore. App. 1992), ruled that a city law prohibiting horn honking for purposes other than a reasonable warning to another vehicle violated the free expression guarantee of Article 1, section 8 of the state constitution."