Can we just take a moment to think about the fact that what Voldemort did to the Malfoys was so bad that even though he didn't even kill them and even though Voldemort regularly tortures his followers when he's annoyed, all the Death Eaters know about it and are scared it will happen to them too and see it as a notable and exceptionally bad punishment?

He must've hurt them so much. I mean Lucius still has VISIBLE marks on him even though a lot of time has passed. And all this happened because Draco didn't identify any of the members of the Trio even though he recognized them, thus giving them a window to escape. And he also didn't put up much of a fight when Harry went to take his wand. He had lived with Voldemort in his house for a long time. He knew what he was risking. And he did it anyway.