I found two active users with identical user names, but distinct accounts.
I was over at math.SE and saw an interesting meta-quesiton. I read it through and I thought I recognized the username of the OP. I have answered a question of an OP with the same name here in CV. Then in a comment the OP states "I am homeschooled and doing math on my own". I say "no, this can't be, the OP whose answer I answered is a biologist taking a stats class". I check the math.SE profile of the user -and it does have a CV account. "Ha!" I think "The guy is playing us" -for some reason of his own (I assume it is a he). Then I check his profile on CV... and the question I have answered to is nowhere to be found. I go to my profile, find the question that I have answered, open it, hit on the OP username... and I end up in a different CV account, with the same username.
Retrospectivly, it sounds fun - but only because I thought I do the above checks before going at the OP in a suspicious tone.
It is rather puzzling (policy-wise) that the system permits the same user name for two different accounts. Obviously the system gets to differentiate the users by the account number, but permitting identical user names can create confusion and misunderstandings for users that see the same user name in answers and comments, which come from different people.
Any info on that?