This makes little sense to me. The dangerous zones are places which can be scored from. A header outside this area is not "dangerous" by that definition. If the ball subsequently comes into a dangerous zone it is dealt with by the defender in that zone. You say "if the zones aren't well set and the ball falls to an attacker there's a strong chance that he will be in too much space". Well, yes. And in a man-marking situation, if the attacker loses his marker there's a strong chance he will be in too much space. In either case the system is being poorly implemented, that's not the fault of the system itself. I don't know, but I would argue (and have done) that it's probably not the system which is at fault but the players. If after a period of time it becomes clear that these players will never adapt to this system, then it would probably be prudent to change it. But I have my doubts whether they would implement any system with total competence! The same could be said of many other teams by the way, this is why set-pieces are dangerous for any team, no defence is perfect (though ours could certainly use more work than most).
