The members of SAG-AFTRA—a joint union for movie, television, and radio actors—are currently striking against the AMPTP (Alliance of Motion Picture and Television Producers) for fair compensation.

Some of the rules for striking actors are fairly self-evident: They can’t, for example, work on a production for any studio that’s a part of AMPTP. They also can’t promote existing work, which explains why actors are conspicuously absent from premieres and other press engagements for buzzy new films like Martin Scorsese’s Killers of the Flower Moon (though Scorsese has proven himself well up to the task of shouldering the publicity duties himself).

What you—and SAG-AFTRA members themselves—might not have realized is that the rules apply to Halloween costumes, too. Per The Hollywood Reporter, the union recently released guidelines for what strikers should and should not cosplay this spooky season.

“Choose costumes inspired by generalized characters and figures (ghost, zombie, spider, etc),” SAG-AFTRA wrote in an infographic. “Dress up as characters from non-struck content, like an animated TV show.”

The organization didn’t come right out and forbid strikers from dressing up as characters from struck content, but it did tell them not to “post photos of costumes inspired by struck content to social media.” That said, it’s impossible to police what other people post on social media, and just because you don’t share a snapshot of you in your Ken or Barbie costume doesn’t mean nobody else will. As THR puts it, “nothing is scarier than getting called out for scabbing.” In other words, a striking actor is better safe in some true-to-life archaeologist’s garb than sorry while suited up as Indiana Jones himself.

This article was originally published on www.mentalfloss.com as Sorry, Barbie! Actors Guild Releases Guidelines for Striking Members’ Halloween Costumes.