It seems it would be rather simple to tell which books are real and which aren't.
I mean, we aren't talking about the Hardy Boys here, with a hundred-thousand different titles. There are seven Harry Potter books.
Memorization, it seems, will take you that far.
Here's my question: why don't they just publish that same seven books illegally? Certainly, it's against even Chinese copyright to publish unauthorized Harry Potter and...'s. It seems they would make more money, and it would require less work, if they just copied the Rowling texts word for word.