After a discussion with doggoman about situations like this we agree that it is the fault of the traitor who announced that they were the last innocent, as this is a form of ghosting because they have revealed their traitor buddies. Consequently the innocent has been told the identity of all the other traitors. I see no reason to deny this given 2B is a good girl and never breaks rules.

It is not ghosting and don't forget that traitors could always lie. I mean there can be 4 innocents left and two traitors and one of the traitors can then say "Oh X you're the last innocent" and it wouldn't be true at all.
If anything it only means that that traitor can be KOSed as they were the ones that revealed themselves to be a traitor.