They know it better than J.K. Rowling herself.
So, when the trailer for Fantastic Beasts: The Crimes of Grindelwald was released, the fans got out their monocle to INSPECT.
The beginning of the trailer shows Hogwarts, something we're all familiar with. However, it also shows what could be a massive mistake. Wizards are shown apparating into the grounds, something we all know is impossible.
Apparition is a form of teleportation that could lose you a limb here and there (casually). In the Prisoner of Azkaban, Hermione tells Ron and Harry that you can't apparate into Hogwarts because it's protected by "more than walls."
We know, Dumbledore does it further down the track but he's Dumbledore and he can (don't @ us).
Anyway, fans were quick to notice to flaw and took to Twitter to let the world know how knowledgable they were in the subject of Harry Potter.
However, one fan pointed out an interesting thought. "What if events in this movie ARE the reason you can't Apparate onto the Hogwarts grounds HMMM."
Watch the trailer below:
Fantastic Beasts: The Crimes of Grindelwald comes to cinemas November 16.