Maybe someone is reviewing a book that they purchased elsewhere? Whose business is it where I purchase (or check out) a book? I don't think erring on the side

Maybe someone is reviewing a book that they purchased elsewhere? Whose business is it where I purchase (or check out) a book? I don't think erring on the side of privacy is a bad thing. I was checking a book out of the library yesterday, and saw at the bottom of the screen that I have an overdue charge. I asked the librarian what book the charge was for. She pulled up my account, and then invited me over to her side of the counter, so that I could read what book I checked out. She was avoiding anyone overhearing what my reading habits are. I was pleasantly surprised.