The first thing that I noticed is that you have a received a generous number of answers/replies to a question that really does not require too much explanation. The second thing I noticed was you asked the question many days ago yet did not even acknowledge any of the replies. The final thing to mention is there are several members that have changed their forum username for one reason or another, it does not automatically mean there is nefarious activity associated with it.
If the user has achieved a high rank in the forum, and choses to change his username, will the account be suspected of changing hand and be tagged for that? If yes how will other users know he is still the rightful owner?