I don't think he would have, and I also think that's why it was done.. to show how different the Family became without Vito's leadership. The fact that Tom (who was acting as Don at that time, remember) would have an innocent person killed only to make a point, nevermind Michael's killing of his brother (no matter how justified it may be) serves to show that without Vito, the Corleone family was starting on a downward spiral.