Hey, this is happening. The folks at GoG are giving away copies of Saint's Row 2 for free (it's a gog-exclusive patch so it won't have the insane speed nonsense going on I believe)
Another related promotion is the wonderful GoG connect feature I posted about on its initial release.
Connect is a new feature that uses Steam's public facing user-libraries to link GoG copies of games to Steam, giving you, essentially for free, a DRM free (and therefore way better) version of the game. If you own the other games in the series on steam and have a public steam library (which isn't really that big a deal) then you can get GoG copies of the game. Icing on the cake is that the GoG copies seem to be coming with all the DLC, so if you for some reason owned the incomplete versions of the game, you'll get the ultimate stuff for free.