No one seems to "get it" though but as you say, a line has to be drawn somewhere. In 90% of cases, it's a non-issue. Only when this imaginary line affects someone personally does it come up.
Speaking of this, my in-laws live in an apt complex. It's in the 800 block of Union Blvd in a nearby city. Their daughter moved into an apt complex across the street and up one block, the 900 block of Union Blvd. Guess what ?? One side of the street was GTE phone service and the other side was Ameritech. It was a long-distance call for them to call each other !!

Why ?? Because of that imaginary line drawn down the middle of Union Blvd.