More on nightwatchman

Interstingly according to yesterday's Times quoting Andy Flower the decision to use a nightwatchman in the second innings wasn't his or even Strauss's but Shah's. Now leaving aside the notion that this appears to be spectacular buck passing and even if the view is that it's the ingoing batsman's prerogative to call for a nightwatchman then I'd argue that the view is wrong and that captain and manager should make decisions of this kind. That's what I thought until discussing it with people who seem to know more about it yesterday when I learnt that apparently it is common practice for the ingoing (or non-ingoing) batsman to make the decision.

Can't be right can it ?