I have tried (am trying) to write a book, and find Anderson's explanation totally believable. Search and Replace is NOT your friend if you don't use it intelligently. What apparently happened is the publisher decided not to use footnotes, but instead of using the footnotes to locate the relevant cites and fixing them (citing them inline or removing them) first, deleted all footnotes, then they tried to locate all the cited text from memory. Poor planning and sloppy editing was the direct cause of the plagiarism, not intent.