Kids fly free?

Apparently Southwest Airlines is serious about being kid-friendly.  During 2009 a woman on one of their flights headed for Salt Lake City decided to have a baby.  Although the crew diverted the flight to Denver, the baby wasn't about to be upstaged and made its way into the world at 30,000 feet.  The lucky guy was ushered in by a doctor and two nurses that just happened to be on the flight.  I wonder if this was a case where "kids fly free"?