They've done things like that quite often, think it's their usual response to being forced to mime live appearances, there used to be quite a lot of older videos of them doing similar stuff on youtube, think the BBC had a real issue with them for a while after Matt swore on a program. I've seen ones where he stands with his arms up in the air not touching the guitar through the main guitar solo of songs or doing a very theatrical, blatantly fake keyboard/piano playing where his hands are obviously not in sync with the music.