What do we mean by "unexpected"? It's clear the defender was expecting a cross of some sort even if he didn't know exactly where it was going, so I think it's disingenuous to suggest that he was caught by surprise!Sorry, an unexpected ball blasted at pace can go absolutely anywhere, high, low, left, right, how possibly can a defender react so quick that he deliberately moves his hands towards the ball, as the law asks us to consider. You as a referee are expected to know that for sure that thats what was going to happen. I'm not getting your logic in this instance. I think this poorly wrote guidance note was aimed at the instance where a defender with his hands out like shovels makes himself bigger, obviously in that instance he has less chance of my sympathy,
And while he's never going to be able to judge exactly where the ball is going, that's exactly why we're suggesting that "making yourself bigger" using your arms should be penalised.