Why do so many airports have rocking chairs?

The Verge:

If I had to pick places I’d expect to see rocking chairs, front porches, living rooms, and pretty much anywhere else would rank far above cavernous and stark airport terminals, yet that’s probably where I’m most likely to see them. And while I could imagine an aggressively whimsical designer somewhere throwing a bunch of rocking chairs in a terminal, I had a hard time seeing how they’d sprung up in so many airports across the country. Why rocking chairs? Where did they come from?

I’ve only ever seen these at the Nashville International Airport. I thought they were just a quirky thing specific to the city.