Where I started we had magnetic tapes, that had to be changed daily. That was done by the staff themselves every day at noon I think, we went out in the tech room, pulled out and stored the tape, took another that was more than a month old from the storage, erased it using a powerfull magnetic board, and inserted it into the recorder.
Obviously they found it to be not very practical the people who were being recorded did have access to the recorder and tapes (and knew how to delete them)
