The Loss of Distance and Justification to Worry

Historically distance has limited what we must worry about.  Our cave-dwelling ancestors only had to worry about being heard, seen or smelled by predators or enemies in their immediate surroundings. 

As time went by large human armies could retreat and separate themselves by 100 miles, which during the Roman era equated to 5 days of marching.  That meant they didn't have to worry about a battle happening for at least 5 days.  Today it is different. One hundred miles equates to mere seconds. The security of distance has died.  Today, we must worry about wider circles.