Could be. I have the impression that less heavyweight shows are less discerning - Good Morning Britain will invite any old chancer on if it gets viewers!
Trouble is, people always notice if it's those who they don't like on. Then you get the screams about it all. UKIP was always a good example as they were running at about 5% in the polls, but how else can the media do it? They can't base it on the opinion polls, they can only do it on performance in the electoral cycle.