At this point the idea was to make it mine continuously whenever the game is running - given that we'd be looking at a lot of machines with not much more GPU power than cryengine requires, and a lot of nvidia systems, we think we'd be lucky to see more than 50Mh/s per running game on average, so it would take quite a lot of hours played before we'd make as much off it as a paid copy.
The idea isn't to make more per copy doing it this way, the idea is to try to distribute more copies and therefore make more overall.