Warner Bros Is Cracking Down On Harry Potter Festivals (apnews.com)
Warner Bros is cracking down on local Harry Potter fan festivals around the country, saying it's necessary to halt unauthorized commercial activity. From a report: Fans, however, liken the move to Dementors sucking the joy out of homegrown fun, while festival directors say they'll transfigure the events into generic celebrations of magic. "It's almost as if Warner Bros. has been taken over by Voldemort, trying to use dark magic to destroy the light of a little town," said Sarah Jo Tucker, a 21-year-old junior at Chestnut Hill College, which hosts a Quidditch tournament that coincides with the annual suburban Philadelphia festival. Philip Dawson, Chestnut Hill's business district director, said Warner Bros. reached out to his group in May, letting them know new guidelines prohibit festivals' use of any names, places or objects from the series. That ruled out everything from meet-and-greet with Dumbledore and Harry to Defense Against the Dark Arts classes. Related story, from 18 years ago: Harry Potter Sites vs. Warner Brothers.
They could also "defend" it by offering an inexpensive licensing deal for small festivals.
Disney does this for school plays. For a small fee you get scripts, rent-a-costumes, and plans for props for "Show White", "Cinderella", "Beauty and the Beast", etc.
Disclaimer: Yes, I am aware that these stories are centuries old, and Disney does not actually own them. But they do own trademarks for many of the characters, and people are far more familiar with the Disneyfied version of these stories than the originals, which tend to be darker and more violent.