The front 7 don't have to stay out to make screens a bad idea, they just have to realize that the quarterback still has the ball and it might be a good idea for some of them who aren't next to the QB to stay near the RB or whoever. In other news, the Bengals and Cardinals called about one screen against the Bears, a team that couldn't get anyone near the QB. You'd think the Bears defensive line and the Packers offensive line would be instantly converted into pure energy when they came into contact, they're that perfectly matched as crappy opposites. Hence they get no penetration and are still sitting at the line of scrimmage when you try to screen pass. The key to a good screen is allowing the d-line to penetrate but not far enough to get a sack. well, if you try to screen against the Bears they'd let them penetrate and then everyone would be confused while the RB got 25 YAC