If you're a DC resident who wants to make a living showing tourists around the city, DC law requires you to pay a $200 fee and pass a 100-question test about the geography and history of DC. Or at least it did until Friday, when a DC federal appeals court ruled that the requirements violated the First Amendment.

In a scathing opinion, the DC Circuit Appeals Court ruled that the district hadn't provided any evidence that the regulations served a legitimate government interest. And because the regulation limited speech — being a tour guide means talking, after all — it didn't pass muster under the First Amendment.

"How does the memorization of addresses and other, pettifogging data about the District's points of interest protect tourists from being swindled or harassed by charlatans," asked Judge Janice Rogers Brown.

Not only was there little evidence that a testing requirement would deter unscrupulous or incompetent tour guides, Brown argued, the regulations weren't even an effective way to protect consumers from misinformation. She noted that DC's lawyers had conceded that "regulations would permit a tour bus to recruit a drunk off the street to pre-record audio narration" — so long as the intoxicated person in question didn't deliver the narration live.

The decision was a victory for the Institute for Justice, a libertarian law firm that represented the plaintiffs in the case. The lawsuit is part of a national IJ campaign to reduce occupational licensing. States across the country have increasingly enacted regulations that are nominally designed to protect consumers, but seem more designed to protect incumbents from competition. Past IJ lawsuits have helped to free hair braiders from irrelevant cosmetology requirements and allow entrepreneurs to compete with incumbent taxicab companies.

For much more on occupation licensing, read Vox's cardstack: