Please, COs break protocol on a daily basis. They just don't leak shit so much to the public. Instead, they do stuff like take highly inappropriate photos of inmates and share them in their little group chats.
Way more than 50%. I'd say closer to 90%. In countries like Norway they have far more COs per inmate and it generally works out better for everyone, although that's only one small reason why. That place gets it right when it comes to prison in ways inmates in N. America could only dream of.