whattimedoweland i see your point re being needed in an emergency.
But fact is, nearly EVERY other airline has a CSD equivalent that is written into the service. I know QF do, AF and LH as well. I'm guessing others are the same.
But for some reason, BA's are not. Even when we lost another main crew on the jumbo they still weren't written in.
This isn't usually a problem, as most CSD's are like yourself and lead by example (ie work!).
But there are a good 20% that are the single most lazy, miserable, de-motivating member of the entire crew. And being written into the service would address this minority.