Shh! 17 Things You Didn't Know About the Wizarding World of Harry Potter, From a Former Employee

"The witches and wizards in Knockturn are in a rotation and are the same ones that work in Carkitt Market and staff the wand magic through Diagon Alley. It's all about presentation. When in Knockturn, they seem to think they can act differently, but Universal holds us all to the same standard in terms of guest interactions."