Had the opposite problem on Friday. Was scheduled to fly ATL to MSP on Sunday, but heard on the local morning news that ATL was expecting WX (snow to be exact) on Sunday. Because of the predicted snow for MSP on Saturday, I quickly changed my award ticket to fly on the 2:30 pm flight ATL-MEM-MSP, so that I could avoid the weather on both ends.
Arrived in MSP on time (even scored an upgrade MEM to MSP). Went to baggage claim to get my one checked bag. About 6 bags came down the chute then nothing. I waited another 5-10 minutes then headed to the Skypriority baggage problem line.
When the agent pulled up my bag's information she promptly informed me that I should not expect my bag because I was standby passenger on the flight? Huh? I had a confirmed reservation. I politely argued with her for about 5 minutes, then she dug further and realized that I had in fact been confirmed on the earlier flight (DAYS earlier than my originally scheduled flight).
She then informed me that I could wait until 9pm for my bag (which was after the weather was supposed to hit) or they could TRY to deliver it the next day. I opted for the delivery.
When the delivery van driver pulled up late Saturday morning, I was frankly shocked that he had been able to make it to our house. I was interested when he opened the back end and I saw a pile of bags, each tagged with Sky Priority tags. Apparently mid Blizzard bag delivery is an unpublished Sky Priority benefit. The only other vehicle I saw that day on my street that day was the US Mail truck. But it is well known that the Postal Service delivers in snow, and sleet, and....
Interestingly, the tag on my bag DID say standby. Apparently the ticketing agent in ATL had goofed.