A number of European public broadcasters have some sort of balance rule along these lines. It can get pretty weird.
A memorable example, in Ireland, during the campaign for the referendum to legalise same-sex marriage, was a radio news article where they were talking to someone in the hotel industry about the potential impact on the industry from wedding bookings. Because of the balance rule, they then had to have on one of the three available complete lunatics they had for all discussions of same-sex marriage to rant about how the gays were going to transgender all the unborn babies or something (due to all political parties supporting the amendment, and the Catholic Church staying out of it, there were a very small number of public figures available to go on the radio/tv for 'balance', and most of them were conspiracy theorists).
Some broadcasters have recently changed the rules around certain subjects; for instance the BBC no longer invites climate change denialists or creationists for 'balance' in most contexts.
I'm uncertain how I feel about it. It can produce truly bizarre results, like the marriage one I mentioned, but it does seem useful in some cases. A major concern I'd have about it is that it certainly _is_ used to spread misinformation and conspiracy theories, especially where one side of the argument is "basically everyone" and the other side is a weird fringe, or where the natural proponents of one side are sitting it out (common on social issues in Ireland, where the Catholic Church is skittish about opposing liberalisation too visibly).
A memorable example, in Ireland, during the campaign for the referendum to legalise same-sex marriage, was a radio news article where they were talking to someone in the hotel industry about the potential impact on the industry from wedding bookings. Because of the balance rule, they then had to have on one of the three available complete lunatics they had for all discussions of same-sex marriage to rant about how the gays were going to transgender all the unborn babies or something (due to all political parties supporting the amendment, and the Catholic Church staying out of it, there were a very small number of public figures available to go on the radio/tv for 'balance', and most of them were conspiracy theorists).
Some broadcasters have recently changed the rules around certain subjects; for instance the BBC no longer invites climate change denialists or creationists for 'balance' in most contexts.
I'm uncertain how I feel about it. It can produce truly bizarre results, like the marriage one I mentioned, but it does seem useful in some cases. A major concern I'd have about it is that it certainly _is_ used to spread misinformation and conspiracy theories, especially where one side of the argument is "basically everyone" and the other side is a weird fringe, or where the natural proponents of one side are sitting it out (common on social issues in Ireland, where the Catholic Church is skittish about opposing liberalisation too visibly).