[helloguillecl]

Actually this sounds like common law to me. But yes, this should be enough to me.

However, if I consent to a User Agreement, do you really think they keep a copy of the specific version of the User Agreement I accepted?

[marcosdumay]

They almost certainly keep a copy of that specific version of the UA. They also very likely keep a log of you agreeing to it. And probably none of those would matter in a court (what you actually say on your site and how reasonable the document is certainly matter a lot more).

Anyway, UA acceptance does not require and does not imply in opt-in to your marketing emails.