I doubt that a famous singer like the Mcguire eould follow Giancana in Sicily and why Giancana should go to Sicily? Could easly stay in Mexico or in other american big city but remaining in Chicago eas a threat for the mobsters.
I think this was before Mexico or during the time when Giancana was still in Chicago and was still the boss...also, I think it was McGuire's idea to visit Sicily but the boss refused, and so instead they went only to Rome and Milano.
This reminds me of another example when Alex wanted to go to Napoli and Ricca told him that he will arrange for Alex not to have any problems over there, obviously because Ricca was an old Camorrista and still had connected family in that same city, while Alex was already a known mobster.
