Comment 3 for bug 1281

One of the pre-conditions for users to merge accounts is that the "from account" (the one that's going to cease existing) can't have any email addresses. I think we should keep this for the admin interface, because if the "from account" has one or more dead email addresses, we don't want to move them to the other account.

If we do this, to merge any account with dead email addresses will require someone with write access to the production database to go there and delete these dead email addresses. IMO, deleting these emails manually is not a big deal, and on the other hand it'll make it harder to cause harm by merging wrong user accounts.