If your blu-ray player doesn't have the Cinavia Infection right now, than you don't have to worry about it and back-up any blu-ray you want to, with HD Audio!
If you up-date and put Cinavia into your blu-ray player, your back-ups will no longer work with that blu-ray player!
Ways around that is to check into Media Players, which are Cinavia Free! Or there are still about 2 new Blu-ray players that out there for sale that are Cinavia Free! One is Dynex sold by best buy!, but I would really check into Media Players! They are just as cheap as Blu-ray players!, and never have to worry about Cinavia again!:)