There is anecdotal `evidence' I have heard of `censorship' that was based on sensible motives. Well back in time, a club in Yorkshire is said to have censored (or perhaps more accurately `rationed') some songs, such as `Streets of London'. This was because so many floor singers would do these songs, otherwise. So the organiser would ration them, and offer floor singers a spot some time in the future, when it would be their turn to sing one of these songs.