Indecipherable static

I've been hung up on the idea of people who drive around listening to indecipherable static.  No, I'm not talking about the new 50 Cent album.  When I worked as a valet, I would sometimes enter cars from a variety of guests for the purpose of putting the cars away.  Intermittently, but more than I ever would've expected, I would valet a car for a folk/pair of folks/group of folks that had the radio tuned to channels which don't come in.  Rental cars, usually, and usually older people.  A married couple, for instance, would pick up a car from the airport, get in, and drive the 15 minutes to the downtown hotel with the radio on -- tuned into pure static.  That sound you get when you're between actual channels.

How could you sit there in your car with your wife, listening to nothing but indecipherable static, and not mind?  I'm saying this was usually turned up to entirely audible levels.  Who is the person who gets to that point?  Will that happen to me someday, when I will be able to be such a dried up, useless person, that I will not even notice that the radio in my rental car isn't actually tuned to a channel, but I'm driving around listening to it?

Specifically, who are these people?  They didn't even take the time to turn the radio off; indecipherable static, at a clearly audible level, was good enough.  I'm wondering if they even spoke to one another, most times.   I'm wondering if it says more about our society, as it relates to our minds and our attention span.  Probably not, but it's an intriguing phenomenon.  You may have never imagined that people would regularly do this, but I'm sad to report that many people (probably unintentionally) engaged in such an activity.  Who are they?