In HP, I don't understand why Muggles accept that Hogwarts, or really any part of magic, is real, much less send their kids to Hogwarts. As it says in P/SS:
“Nobody in my family’s magic at all, it was ever such a surprise when I got my letter, but I was ever so pleased, of course, I mean, it’s the very best school of witchcraft there is, I’ve heard – I’ve learnt all our set books off by heart, of course, I just hope it will be enough – I’m Hermione Granger, by the way, who are you?” - Philosopher/Sorcerer's Stone, Chapter 6, The Journey from Platform Nine and Three-Quarters
Here, Hermione says that she (and presumably her family, since they let her go to Hogwarts) was "ever so pleased" to find out she was magical. However, how do the Muggles believe this? How can they simply just read a letter, assume that the magical world they are not allowed to interfere in is real, and send their child to a school in the magical world?