Just to expand a couple of points:
At maximum range the danger area excludes everything except a ring a foot or two wide out at the edge, where the projectile is coming down at a very steep angle. Inside that radius, the bullet is too high in the air to worry about.
And the danger area with slugs may be longer than generally thought. The PA game people had a study done, which concluded that slugs are almost as dangerous as bullets, when fired level, or close to it. Seems that slugs are much more likely to ricochet for long distances.