I got something like that in HITMAN (on Steam) a couple days ago. From what I can gather, it's a way to prevent people from cheating, saying it looks at a bunch of stuff on your computer regarding the game, etc. etc. And you'd have to agree to the terms or be permanently in 'off-line' mode.
There were several paragraphs saying what they'd do, and that it was all due to some UK law, or something from over in Europe. With all this insanity going on over there (they're essentially trying to be the thought police) makes it all reek to high heaven of 'Big Brother'.