That user posted this bitcoin address : 1JWsFCv2u47gkgSimeCAznQWwxaQiLiacr in June 2011,I don't find any other address added in his post history so he need to sign in a message from that address to verify the ownership.
Without strong proof that OP is the actual owner, I don't think DT will tag the account. Also, DT should not tag, IMO.
We can saw many accounts has been tagged by using the reason of changing in their posting behaviour and long time gap between posts.And the current user of that account is wearing signature so it maybe bought for joining in bounties.
From BPIP that account's password was changed recently.Is it not enough that account was bought?