The owner, licensee or operator of a visual or sound radio broadcasting station or network of stations, and the agents or employees of any such owner, licensee or operator, shall not be liable in damages for any defamatory statement published or uttered in, or as a part of, a visual or sound broadcast by a candidate for political office in those instances in which, under the acts of congress or the rules and regulations of the federal communications commission, the broadcasting station or network is prohibited from censoring the script of the broadcast.