Does this not make the job of a referee even harder, simply because they are not level with the defensive line? i would have thought if the linesmans only job was to follow the defensive line, then they only concentrate on offsides and if the ball goes out of play at a corner. A referee tends to be in a good position to see which way a throw in or corner goes (i.e. deflections), foul throws, foot over the line from throws etc taking some pressure off linesmans. only a alternative thought to the discussion