Devils4dvocate: I less and less sure now.
From the GOG FAQ;
When can I download The Witcher 2?
You will be able to predownload the game after you purchase it. You'll get almost the entire game and, on May 17 at 07:00 AM GMT, you will only need to download a tiny chunk of the installer and you're good to go.
Of course you'll be able to redownload the game as many times as you like, should the need arise.
From the thewitcher.com FAQ
Information on the release date and on the activation of the game.up
Activation and playing the game will be possible:
- at 00:01 hour at the night between 15th and 16th May for the Collector's Edition
- at 00:01 hour on 17th May for the Premium Edition
- at 09:01 hour on 17th May for the digital editions
If you attempt to run the game before the dates given above the program will close without any warning immediately after entering the Product Activation Code.
So... the GoG.com version (and other digital editions) is the last to activate, though they told us that we'd be the first to play the game, that we were supporting the developers, though we have 9.6Gb of the Witcher 2 since 10th of May. Great job.