If Don Vito Corleone was reckless or stupid, he would have spoken explicitly to his underlings about what he wanted done. But he didn’t need to. All he had to do was raise an eyebrow, give a look to Tom Hagen, imply what he was thinking.
And so he didn’t say “tell Clemenza to have his men beat the living shit out of these animals. Don’t kill them but definitely spill their blood, break their bones, make them weep with pain. But don’t kill them — that wouldn’t be justice.” Instead he said, “Give this to, uh, Clemenza. I want reliable people, people who aren’t going to be carried away. After all, we’re not murderers, despite what this undertaker says.”