Yes this would also be good since a sensible reason for this to happen is because forgetting you added this book before. Some tbrs date back to many years ago, this warning could prove helpful and make you realize oh I should probably read this now since it has peaked my interest x amount of times years apart (perhaps a hidden 5 star)

I would also appreciate this option, it would definitely help to track larger libraries and when making purchases in shops! ❤️

Oh, the reason it works now without a warning is because of the very reason you state needing a warning! I figure it's rare for people to have multiple editions of the same book and most of the time they do want those different editions in the app, so this would add extra friction...but your feedback is noted! This is the first time we've had such a complaint in the seven years we've had this feature, but that doesn't mean it isn't a valid request.