A few tips to a second-hand charity book dealer:
-Life, the Universe, and Everything is not non-fiction.
-Whatever you may think of their authors' respective prose styles, Fifty Shades of Grey and the Book of Mormon do not belong in "YA."
-If a book's cover identifies it as a "crime novel of Detroit," it most likely shouldn't be filed in "Science Fiction and Fantasy."
-Debates rage over what constitutes "fiction" vs "literature," but I'm going to go out on a limb and say that James Frey's A Million Little Pieces does not qualify as the latter.
I recognize that sometimes customers move things around, but surely that can't explain everything.