This.
Everyone time the Mexican wave crashed at the Carlisle fans, all the Saints fans nearby booed. During one of the 'waves', ML's face came up on screen and loads of people cheered. As the camera panned away and the cheers died down, the 'wave' ran up against the Carlisle fans again and Saints fans nearby booed them. It had been going on for some minutes by then and was all fairly light-hearted stuff. It would be easy for anyone who wasn't watching the mexican wave action to misinterpret it, but I'm pretty certain it was incidental.