The BO line also causes an AR to have to pay more attention to their offside positioning/watching. Some coaches get cute and station a player right at the BO line. For an AR, staying with '2nd to last', could mean that they are further away. Since the player is not offside, when standing inside of the BO line, a hard kicked ball to them gives an immediate direct goal attack. The question becomes did they break the plane of the BO line, before receiving the ball. The AR would possibly have to run like crazy to get back.