Rich,
I used to live over that way. Lanier is wall to wall party boats in nice weather and still busy with fishing boats in the cooler months. Also, the shoreline is lined with lake homes and docks. There are a lot of resident white bread eating mallards and Canadas, but while I believe it is still "legal" per the corps to hunt on the open water, you will generate lots of phone calls from lakeside dwellers to the various LE agencies that have jurisdiction around and on the lake once you start shooting. Lanier is located close to a metro area of several million people, many of whom recreate on the lake. If I am not mistaken, it is the busiest (meaning most crowded) of all the lakes that the Army COE manages. If I still lived in Georgia, Lanier would be the absolute last place that I would attempt to duck hunt at. Hope this saves you some time and aggravation!