I'm opposed to registration of anything on the grounds of privacy.
I've purchased hundreds of computer games over the last decade and I cannot recall registering any of them.
I don't like a culture that passively accepts the registration of anything ranging from automobiles and dogs/cats to firearms and computer games. I won't participate in such a thing.
Quite frankly it's my own business, nobody else’s.
I've read typical licensing agreements and they state that I can only use their precious software on ONE and ONLY ONE computer. I happen to have multiple computers in my house. I will install and use software on however many of my computers that I wish to, without being told otherwise. This is just one of the reasons I am specifically opposed to registration of software.
You're free to register every aspect of your life and every one of your possessions, I'm not going to go down that road.
You've already given Paradox more information about yourself by signing up for the forum, all registering the game does is enter a code which tells the forum that the username Koevoet owns the game HOI3.