Vito's policy was to give orders to one person at a time, so that if anyone turned rat, prosecutors wouldn't have a corroborating witness--someone who'd testify that he'd seen or heard the same things that the rat testified to. We saw this when he told Tom to tell Clemenza to beat up the punks who ruined Bonasera's daughter, and when he gave Luca the order to infiltrate the Tattaglias.

So, why did he have Sonny, Fredo, Tom, Clemenza and Tessio present when he met with Solozzo? You could argue that he wasn't giving a criminal order--he was actually turniing down a criminal partnership. Why would he need witnesses for that? Your views?