If the cop does reveal himself then it's more a case of it being negative; if they're lying and we don't believe them, we lynch a mafia. Good call. If they're lying and we do believe them, we help the mafia. If they're telling the truth and we don't believe them, we lose a cop. If they're telling the truth and we do believe them, chances are they'll die the next round. So really the cop saying they're the cop (even if they're not) is a sure fire way to either get yourself lynch or killed. In a normal mafia game it's common for the cop to only talk to players they feel they can trust. So just because the cop hasn't posted here doesn't mean they're not doing their job.
