My family's helping me fly back home for the next book because we read them aloud together. We also read Bible stories together. Thing is, we know the difference between real and make-believe because my parents carefully taught us what was right and what was wrong from day one. My brothers have all figured out that magic isn't real, after all, no matter how many times they jump off the roof on a broomstick, they haven't managed to fly yet.
If you tell them to keep trying, perhaps they'll achieve "greatness" ... or else, they might just end up like this guy, a "practicing wiccan":
http://www.freerepublic.com/focus/f-news/1383757/posts