I disagree I think it is a flaw in the storyline. Carlo is part of the family he lives and works with the Corleones. He knows what they are capable of. Why would he go on a suicide mission to get his revenge? His roll in Sonny's death is painfully obvious and he does not even have the sense to leave town!He continues to hang around the Coleones.Barzini etc could promise him anything but what good is it if your dead?I can go along with the Paulie explaination but the Carlo thing is just too much of a stretch.