Way, way back in about 8th grade or so, we all had to take a basic laws & civics class. I recall something about financial dealings & contracts entered into with minors were not valid, and the parents could demand a refund of all monies if a business entered into a financial agreement with a minor. I don't recall the specifics, though, but there were exceptions if the product was a consumable... I think. (I just don't remember the specifics). Something about if a child bought a candy bar and ate it, no refund was due, but if a child bought a car and drove it, 100% refund was due with no allowance for wear & tear, loss of value, etc.
So... maybe SWA refunded the money because they realized that legally they weren't allowed to enter into the agreement in the first place? Or, is airline travel considered a consumable product from a legal standpoint? I don't know the answer.
On another note, how did kids today become so sheltered? I remember in the 70's and 80's being MUCH more independent than kids today (traveling alone without any Unaccompanied Minor programs on connecting flights across oceans, going out to play and not coming home until the street lights came on, using buses and trains to take day trips in the summer to nearby cities & amusement parks).