There's a little more to it than just leaving the stroller at the gate.
We've gate checked a wheelchair on various airlines for 15 years, so I'm kind of an expert on gate checking.
When you first check in, let the clerk know that you want to gate check a stroller. They may give you a gate check tag right there or tell you to check with the gate agent. If you wait until you get to the gate, ask well before boarding begins, not as you are walking thru the gate.
You will be given a gate check tag, which is similar to a baggage tag. usually they are bright neon colors -hot pink or neon green so the tag can be seen easily by the baggage handlers. Sometimes the gate check tag has only one option - to have your stroller delivered to the gate at the next stop. Sometimes, there are other options - the gate or baggage claim at your final destination or a city where you are changing planes. Make sure you know what is marked on your tag. (This is also why you don't want to just leave it at the gate. The chance of the tag being marked incorrectly is much greater if the gate agent is hurrying to do it while boarding is going on.)
If you do have it delivered in Atlanta, make sure your layover is long enough to pick it up and get to your next flight. They take strollers and wheelchairs off fairly quickly, but don't expect it to be waiting at the door if you are the first off.
When you leave your stroller at the gate, make sure it is folded and everything is secured so nothing will pop open and possibly be damaged during the trip. If you have added things like cupholders that can be removed, it's best to take them off so they won't catch on anything. Also, fasten seatbelts so they don't get caught or tangled.
The last thing is to remember to pick up the stroller. We are usually among the last off the plane and on almost every flight, we see a stroller or 2 still waiting at the gate for pick up when there are no kids left on the plane.
