Don't think Ian MCLachlan was able to initiate actions to the tune while playing the accordion...

I'm wee aware of old Davy Stewart's version of 'I am a miller tae my trade' while simulating the sound of the mill wheel by using his hand & elbow to simulate the sound of the mill wheel- can't remember how he did it, or I might have a go sometime- very effective & entertaining- from a source singer & certainly not an 'annoying fad'.