AND CD project is offering it for DRM-free on the one distribution channel it has control over. I would say it be more likely that it's the publisher's making the decision.
Zeewolf: I don't buy that. Note that there are at least three different publishers working with CD Projekt on worldwide distribution. CD Projekt themselves being the fourth. And the DRM is the same on all retail versions.
Yes and that may be the deal they cut for the retail version - in fact that would be a perfect explanation for it. They need to use the other distributor's access to get the physical product out to countries around the world. To do two or more separate retail versions would not be particularly reasonable from a business standpoint. They cut a deal with the publishers who insisted on using DRM - all of them do, especially their current partners, but that wouldn't change from publisher to publisher. Atari and Namco put DRM on their stuff and like it, it is more reasonable that DRM on the retail version is at their insistence.
Besides which I quite like this since we have a (relatively) controlled experiment in DRM and consumer preference. Consider how you buy to be a vote in determining the future and necessity of DRM.
PS I should note that I am not planning on buying the Witcher 2 but that's because I don't play RPGs :) and buying a AAA title new simply to support DRM-free gaming is not how I want to spend my money. Now if they released a great new AAA DRM-free flight-sim or space-sim or 4X strategy game, that would be different :P