Not only that, but the checkpoints didn't even start until just in front of the boarding area. I remember the huge stink (although it may have been pre-911) when O'Hare decided that no one would be allowed in the concourse unless they had a ticket. Whereas I remember my mom taking a couple flights to my grandma's back in the mid 80's, and watching her board the plane and watching it take off from the terminal window.
