Quote ="inside_man"The rule I was always tought was that the keeper covers the side of the goal which the wall doesn't.
If the ball goes over the wall and in - it's just a good freekick.
If the ball goes through the wall - the wall is at fault. Simple.
If Milner hadn't moved, that goal wouldn't have been scored, the keeper put him in that position for a reason.'"
All of those points are correct. The fact Walcott waves at Milner as if to say why did you break from the wall as soon as the shot goes past them says it all. A keeper has to trust his wall to do it's job while he covers the part of goal not protected by the wall.
If a keeper wants to cover all of the goal himself from a free kick then he wouldn't ask for a wall at all.