OK - Thanks. She was swamped and I figured that I had gotten away with something. Since I had no bags, I did the bags-free kiosk check-in at ATL in the tunnel coming from the parking garage. I didn't even think about the return pass until I was having my second (or third) cocktail in 3A.
It was a bit sad seeing the ocean and palm trees from the plane, then from the terminal and then from the plane again without stepping outside... I might have to make the next one an overnight.
But, I purposefully did not want a MR in Dec in the midwest or northeast due to the possibility of weather issues.