The Stark Trek franchise has always had one of science fiction’s most active and enthusiastic fan communities. Creative as they are prolific, those admirers have penned whole libraries of fan fiction and even produced feature-length films of their own. Though such unofficial projects likely helped the Star Trek universe maintain its broader cultural purchase, the property’s corporate parents have long pushed back against them. Now CBS and Paramount have firmed up their stance, issuing a list of rules that amateur filmmakers must follow if they want to distribute their Star Trek-inspired work without being sued.

Though many of the conditions are structural—including a 15 minute cap on stories—the most striking rules are those that establish strict moralistic guidelines for filmmakers. “Videos must not include profanity, nudity, obscenity, pornography, depictions of drugs, alcohol, tobacco, or any harmful or illegal activity,” they read. These limitations are obviously designed to protect the reputation of the franchise and its characters, preventing them from being dragged down into the mud. But it’s also a transparent attempt to resist the tradition of more transgressive fan appropriations, a tradition so well-established that it helped create an entire literary category.

Unsurprisingly, though, Star Trek’s owners seem most concerned with maintaining their own revenue streams. They insist, for example, “The fan production must only be exhibited or distributed on a no-charge basis and/or shared via streaming services without generating revenue.” More strikingly, they claim that filmmakers must use official costumes and props in their films rather than “bootleg items or imitations of such commercially available products.” In other words, if you want to make a free Star Trek film from which you will never make any money, you must first pay Paramount for the privilege by purchasing official costumes and other props.

Along similar lines, the new rules severely limit the amount of fundraising that filmmakers can assemble for their projects. In the past, fans have sought backers for their work on sites like Kickstarter, with one project accumulating more than $600,000. The new rules look to prevent similarly successful campaigns in the future, declaring, “CBS and Paramount Pictures do not object to limited fundraising for the creation of a fan production … so long as the total amount does not exceed $50,000, including all platform fees, and when the $50,000 goal is reached, all fundraising must cease.” The intention of this provision seems clear enough: While the franchise’s corporate parents are happy to have filmmakers well-funded enough to buy branded merchandise, they don’t want them to show up the series official installments.

Ultimately then, the rules come down to this: Long live fan films, but only if CBS and Paramount remain prosperous.