Blizzard recently issued a hotfix for Diablo III over the weekend. Supposedly this hotfix was to make a number of quick changes that weren't addressed in the patch released earlier in the week. Turns out, the hotfix was for something far more serious. Item duping.
Well their is one point for people against Blizz DRM not stopping anything. I personally was of the stance that if it stopped duping, I didn't have a problem with it but those people are crafty. It has been hotfixed but begs the question how long before another work around is found.
forum post on how it worked.