From Fredo's dialogue it seemed to me that he was never in Cuba before.
He pretended to be new to Cuba just to trick Micheal into believing he didn't know Roth.
Interesting theory, but one I don't completely subscribe to. We all know that Fredo wasnt smart enough to trick Mike, and it appears that Mike was completely taken back when Fredo made the revalation of Johnny Ola at the superman show.
I also think that Mike was constantly aware of Fredo's movements while he was in Las Vegas, and if Fredo was gone for at least 3-4 days, Mike would have known and questioned Fredo.
