The display name is a dead giveaway and the user might not want an 'official' confirmation or links between both accounts. I am not only speaking about this case but in general, if the account owner does not link both accounts, others should not do that for them through a tag.
- Jay -
Where do you get that from? Leaving a neutral tag and sometimes even negative on alts accounts when they are discovered is something commonly done by DT members on a regular basis. Regardless of whether the owner wants to or not. It is left negative if one of the alts already had negatives, and neutral in all other cases.