Um, maybe I'm just dumb. Maybe I don't have enough experience with what the haters deem as GW and their unfair practices. Maybe I'm just reading less in to the shipping note.
Where does it say that quantity is limited? It only states that if you order by X day, they will process the shipment on W, M, etc following. It looks to me on the surface of the note that they are attempting to gage inventory management. Not necessarily limit product. GW is likely similar to most businesses now a days that work on just in time inventory and they don't want piles of excess sitting on their shelves waiting for B&M to order it.
Anyway, again I don't see where they are saying you can't have 50 Wraithknights. Only that if you wait to order, it might ship later. Heck I was in the electronic industry for 20 years and we always did that with new releases to assure that everybody got some product rather than having to tell a customer we were out of stock on day 2.
just my humble 2 cents