Very strange. I mean, even if they don't like the act it's still unprofessional of them to not give a standing ovation. Especially when they've given them to much worse.
The only time I remember the judges not giving the guest artist a standing ovation or even an applause, was when Jamiroquai was on the show back in 2010 and he had said some really rude things in the press about Cheryl Cole and Dannii Minogue a few days prior.
