You can add another name to the growing list of game developers that have decided not to bother copy protecting their games. Polish game studio Flying Wild Hog apparently realized that a) all DRM mechanisms are eventually defeated; b) DRM is costly and time-consuming to implement; c) DRM is annoying to paying customers; d) DRM increases support costs; and e) their efforts would be better spent on improving their games.
The result? Their most recent (no-DRM) game, Shadow Warrior 2, is selling extremely well on Steam. Sure, some people are no doubt 'stealing' the game, but those people will always find a way to do that whether there's DRM or not.