South Koreans staged a “ghost protest” with holograms on Wednesday because the real-thing wasn’t allowed.

The rally was organized by Amnesty International on the eve of South Korean President Park Geun-hye’s third year in office to protest his suppression of free speech. For roughly 30 minutes, the transparent projections marched through Seoul’s Gwanghwamun Square before a crowd of roughly 100 chanting: “Promise us democracy! Promise us freedom of assembly!”

The application is new but not so much the technology. In this case, 120 volunteers were filmed across a blue screen to be projected at Gwanghwamun Square while people were encouraged to upload a recording of themselves chanting to the Amnesty website. Supporters could also upload phrases to be used on virtual picket signs.

Domestically, we’re still sorting out whether holograms have free speech and South Korea is no different, though the stakes are much higher. The group only resorted to “ghost protest” when authorities told them an actual one would violate South Korea’s demonstration laws, and police took photos of the holographic participants in Wednesday’s rally. If identified, those virtual protestors could still face charges for violating the laws regulating assembly and demonstration and, if convicted, could be sentenced to as much as two years in prison or a two million won fine.

Protesting is risky business, even in America, where citizens are supposed to enjoy First Amendment protections. Last November, the NYPD arrested more than 50 people at City University of New York’s Manhattan headquarters demonstrating for the innocuous cause of a faculty raise. The same department arrested another five protestors in December during a somehow-more-controversial Black Lives Matter rally at Rockefeller Plaza. But South Korea has far more draconian laws that can be used to imprison people for voicing anti-state policies.

“If the event includes chanting indicative of a collective opinion, it can be considered as a demonstration, and this means the rally would be illegal because the organizer did not report it in advance,” police commissioner Lee Sang-won told the Korea Times.

It’s not the first hologram protest, though. In April in 2015, activists with the “Holograms for Freedom” group protested in Spain for a similar reason — actual protests were not allowed.

Photos via YouTube