They are charging enough to make some cash. I guess as long as they don't advertise it as a Harry Potter themed LARP they will be OK. But if they get enough coverage where people write about the Hogwarts LARP, then they probably will be in some trouble.
Ah, so the info I have on that that I have is this- In Poland they were able to run it as a 'Harry Potter LARP" because they had some sort of special permissions (Edit: no, my mistake, I think there was just some advertiseing done calling it that but it wasnt by their hand, even in Poland it was a NEW universe). I assume there are some differences in copyright situation over there- now over here, they are running it as a 'wizardry school' thing, while yes inspired by, it is not a Harry Potter larp, it is not the same universe, and there are no direct ties to those materials and they state this openly. They know what they're doin : )
Well... given this is what their previous kickstarter looked like https://www.indiegogo.com/projects/college-of-wizardry-a-larp-for-witches-wizards , not even calling themselves a harry potter larp (Evidently they did NOT call themselves a harry potter larp over there, atleast not officially so my bad- but other people have always called them that and theres even confused memes floating around )... I think they'll be fine : ) - mind you this is a one-shot style game not an ongoing.