Hong Kong protesters are putting together a “Halloween masquerade” for Thursday, complete with downloadable templates for masks.

Masks were made illegal by executive order in early October, with a nominal exception for medical masks that protesters have enthusiastically exploited.

That loophole in the rules probably would not stretch to cover masks of Pennywise the killer clown, the Joker, Jason Voorhees, or Chinese dictator Xi Jinping, who are among the options available for download, but a limited exemption was made specifically for Halloween masks. The precise limits of that exemption are a matter of some confusion, but the police said they could ask revelers to remove their masks if they begin chanting protests slogans or engaging in other political activities.

Hong Kong police declared the proposed Halloween gathering to be an “unauthorized assembly” that could “impose a serious threat to public order and public safety.” 

Business owners were advised to stand by for police advisories to “close earlier if necessary” on Thursday to ensure “the safety of lives and properties.”

That could be a problem for Hong Kong’s entertainment industry, which views Halloween as a major event for both adults and children. Since the mask ban covers face paint, stations have been set up around popular children’s attractions to help them remove Halloween makeup before venturing back onto the street. The protest movement derided such services as a grim example of Hong Kong’s increasingly authoritarian trajectory.

Protest leaders said they would march even without police permission along a route that will take them past the most crowded bars and clubs. Some of those areas were seen as dangerously overcrowded on Halloween long before the current protests began.

The police announced plans to deploy 3,000 riot officers and several water cannons on Hong Kong Island, establishing an aggressive early presence on Halloween evening to discourage mobs from forming.

“We will carry out stop-and-search operations in various locations including MTR stations and intercept vehicles that we suspect are being used to deliver supplies of weapons, petrol bombs and protective gear to protesters on the front line,” a police source told the South China Morning Post on Wednesday.

“Police will take action if radicals build road barriers and set fires,” another source said.

Business owners said they feared clashes between protesters and police could shut them down on a lucrative evening. At least one major event, the Ocean Park Halloween Fest, was canceled in advance.