They knew it would be dangerous, they knew what happened the three years before at hogwarts, and yet they still held it? I know they didn't know Voldemort was back and everything but they knew it was dangerous. Also Dumbledore said something about being suspicious of MadEye all along, so if he were suspicious of his why did he let him put in the cup in the maze? Also moral of the story, always listen to McGonagall.