Librorum Prohibitorum

I just read a book about books, and one thing I found out is that in the 16^th century, when the Vatican banned certain passages in let’s say a text by Copernicus, some people would draw a line through those parts lightly so that they could still be easily read. That way, you could see what it was that was being forbidden. So maybe libraries should add stickers that identify a book as one somebody wants removed, explaining who they are and their reasons. That seems fair. That’s the difference between a war of ideas and a war on ideas.