Again, I don't hold it against them from trying to protect their product but this is going to gut what remains of their PC sales. If there's going to be DRM it's got to be provided by the platform (i.e. Steam or Games for Windows Live) simply for usability reasons. Publisher specific DRM layered on top, especially when it requires yet another account to manage and a password to remember, just becomes another bother.
Also, as many others have already said, this is going to be a support nightmare for Ubisoft when it goes live.