A good point, Ian, but, like I said, play with enough flash when you ARE playing the keyboard, and make sure it doesn't 'flash' by itself while you pick up a secondary instrument (there's NO WAY I would ever walk away from the keyboard and sing... I don't book myself as 'karaoke'), and they pretty much 'get it'.

As long as when YOU stop playing, YOUR parts don't continue, it's pretty obvious what is happening... In fact, one more reason to play as much as humanly possible yourself, and only use the basic rhythm section of the arranger, or SMF of the same. Show them that it's YOU playing it by the simple fact that it STOPS when you do something different...

But walk out into the audience while NOTHING changes in the backing, and they have every right to assume that's all you are EVER playing...