Is the BBC stacking its audiences against UKIP?

'... the BBC could be spicing up its debates by placing people in the audience "who can be relied on to take a rehearsed and provocative line" after producers identify them through BBC-run phone-ins where their names and opinions have been logged for future consideration as audience members. '

More here http://www.ukip.org/newsroom/news/1000-is-the-bbc-stacking-its-audiences-against-ukip

To be fair it's not just UKIP that the BBC rig their audiences against, it's the Conservatives as well.