In DR2 in the second case, Peko's logic confuses me. Assuming nobody, including Monokuma, would buy the silly tool logic, which is absolutely something she should have assumed, by trying to get away with it, she was putting Kuzuryu's life in danger, which seems like something she wouldn't want to do. I don't really think it was thought through very well.
Their logic was Fuyuhiko was the killer, he's the actual blackened because she's just a "tool". So everyone was wrong when they voted for Peko and thus Fuyuhiko get's to walk away free.