A gathering to celebrate U.S. Supreme Court Justice Ruth Bader Ginsburg's 86th birthday Friday afternoon won't be an ordinary event.

Instead, 500 of her enthusiastic followers have decided to follow her lead of physical fitness by dropping to the ground and planking in front of the Supreme Court. More than 2,000 others have expressed interest in participating.

“Plank Like RBG” is the name of the event, and an outfit called The Outrage—dubbed by Washingtonian Magazine as a “resistance retailer”—is organizing it. The event's Facebook page notes that Ginsburg has said the most important person in her life now is her trainer.

Reports of other RBG birthday celebrations have popped up online in places including Brooklyn, New York, where a rally is set for Friday to promote the idea of naming Brooklyn's municipal building after Ginsburg, who was born in the borough in 1933.

As for the celebration outside the Supreme Court, Outrage official Michelle Howell said it will not be a protest as such. “We use joy as an act of resistance,” she said.

Early reports stated that the participants would plank on the marble steps of the Supreme Court, which would make for a compelling photograph. But Howell said that in conversations with court officials, her group was told that no such thing could take place. “We assured them we would not be on the steps. We'll be on the sidewalk,” Howell said.

Federal law, Supreme Court regulations and a 1983 Supreme Court decision, taken together, forbid demonstrations on court property that could disrupt the order and decorum of the court.

“It is unlawful to parade, stand, or move in processions or assemblages in the Supreme Court Building or grounds, or to display in the Building and grounds a flag, banner, or device designed or adapted to bring into public notice a party, organization, or movement,” according to the federal law, 40 U.S.C. 1635. Such events are confined to the public sidewalk in front of, but not the property of, the court.

But Mark Goldstone, a Washington lawyer who has defended dozens of protesters arrested on the court plaza or inside the court itself, said that only a “very strained interpretation” of the law would forbid an event like “Plank like RBG.”

The event, as planned, is not a protest, does not disrupt court decorum, and the only message it is conveying is birthday wishes for a Supreme Court justice. As long as the plankers don't block ingress or egress into or out of the building, Goldstone said Ginsburg's fans could lawfully plank on the steps. The court steps are no longer used to enter the court.

“The court is taking the awkward position that a celebration of Justice Ginsburg's life and birthday is non-decorous,” Goldstone said.