So why doesn't Party B laugh in their faces and say, "Yeah, publish and be damned." If party B puts even a moment's thought into it, they will see that Party C works with or for Party A, and the whole thing will blow up in Party A and Party C's face if the truth gets out, as much, if not more-so than Party B who can turn state's witness or equivalent to avoid the worst of the prosecution. The fact is, Party C's threat is hollow, and only a moment's consideration of the situation would reveal that to anyone. It is a hopeless blackmail ploy, as the blackmailer and his confederates are more guilty than the person allegedly being blackmailed, and any revelation will hurt them far more.