User blog comment:New Dalek Paradigm/Urgent - Regarding a New "Chat Rule"/@comment-4052371-20130404001751

Okay, after talking with the admins, I can now confirm that duplicate accounts and impersonation will no longer be enforced by moderators after the move to Brickimedia. The mods are supposed to report the accounts to the admins if they have a good reason for suspicion, but the CMs can only ban dupes or impersonators if they are breaking other rules.

This is because the admins have better tools for dealing with and detecting duplicate accounts. CMs cannot check IPs or IP ban users from chat, so banning duplicate accounts isn't an effective way to deal with the problem.