Not only could you, but some airports counted on it. Midway Airport in Chicago was just completing a massive rebuild in 2001 and the new terminal had (has!) a

Not only could you, but some airports counted on it. Midway Airport in Chicago was just completing a massive rebuild in 2001 and the new terminal had (has!) a big area immediately behind security that was designed as a meeting place with cafes for people seeing someone off; the way it's designed there's no way to move security the other side of this, and so it never took off the way they intended.