From what I heard from an Ubisoft employee, AC2 and Silent Hunter were not using the full potential of the DRM scheme because it was added late in the dev phase.
For Settlers 7 it apparently uses it fully: most of the game economics processing is done on the server. A crack is still possible but that would mean recreate the economics engine completely by analyzing the answers from the official server.
Very sad DRM, I already stated to this guy that I wanted to buy AC2 to play it but that I will not (and I won't pirate it either). I just consider Ubisoft games as non existing until that crazy DRM is removed (which won't happen I guess).