"Without getting into the nitty gritty details, NVIDIA provides boards to our developers for their in house game development. These boards are meant for the sole purpose of inhouse engineering and QA. In the case of the recent GeForce 7800 GS PCI Express reviews that you may have seen, some of these developer boards were mistakenly given out to end users at an event the developers sponsored. These boards were never meant to ship in the open market."
Mistakes do happen, and it's nice that nVidia will be replacing the boards won. This might make those who have a GS hold on to them for the rarity factor. Those who do have a 7800 GS can get a 6800 GS or 7800 GT as a replacement.