Restrict via IP address, problem solved. I didn't mind online activation, but why it isn't tied to your IP address i don't know, rather than some limited install BS. I know IP addresses change btw, what i mean is that it is only allowed to be played on one IP address at any one time. The only way it can know how many times you have installed on different machines is via the internet, so why not use it properly.
Then, we equal consoles. If i want to play around my mates house with a game for a LAN match, i take game round. It's still only being used by one person, hence legal. DRM is completely flawed in every way, and as for Steam,well i like control over my purchases and i'm not paying $60 for something that technically, i don't own.
But if i'm wrong here, then lending DVDs to mates is also illegal.
Edit: Prime example of this limited install crap is Windows Vista. If i change my Motherboard to upgrade, Vista doesn't work.