Yes. Puzo makes the point, more than once, that Vito taught Tom never to make a threat. Early on, during Vito's rise, he gets a contract to truck booze from a bigger criminal enterprise. They accompany the contract with a threat, which "diminished" them in Vito's eyes. The best example was when Tom called Carlo after Sonny's assassination. He said, in effect, "Some men will come to your home. Just tell them to call me. Don't say anything else. No one will blame you for Sonny's death." Puzo wrote, "The Don had always taught Hagen never to utter a threat, but Carlo got the message: He was a hair away from death." Nicely done!