DT tag is definitely required for spammers cheater multi accounts like this. So give DT1, DT2 tag as soon as possible (thanks).
Based on what? Multiple accounts are allowed on the forum and the bounty rules weren't broken, there's no restriction against having multiple Bitcointalk.org accounts registered in that particular bounty:
General Rules- Signature stakes will be distributed every week, other stakes will be calculated end of the campaign.
- First week of the bounty campaign will start on 1st of January, Monday.
- For any questions regarding the bounty campaign write a post to this thread and you will be replied asap.
- We reserve our right to eliminate you if we think you haven't been honest with your work.
- We reserve the right to change bounty campaign rules.
Maybe the user is a spammer, but he hasn't broken any rules that warrant a DT red-tag in my opinion.