Because... they... don't already have your Square Enix ID and Content IDs linked to your forum account?

Really?
Who's to say they can access that information on a whim? tracking out your character names etc, and even if they can I doubt they would bother. However having the name show up right there that is quite another thing. Then that person contacting you asking for help and stating the name that sticks out as being one that p***ed you off? Yeah not quite the same thing.