The only true foolproof method, though, is to get into the habit of having your own gear stowed away in your carry on by the time the landing gear comes down and always checking the seat area and seat pocket for things you may have stashed there.

As for the OP's iPad, I'd give it a day or two to find its way into the right place before giving up hope. ATL is a huge station. Something may get turned into a supervisor by an aircraft cleaner who might in turn forget to forward it on to lost and found. Also, some aircraft will go off to maintenance and not get cleaned right away or if they're pressed for time to turn the plane around, the cleaning job may be rather cursory.