Well, I didn't know...
I remember being utterly shocked - flabberghasted - the very first time I saw the film - that Michael really did have him killed. I guess I'm just as much of a dull blade as Fredo was!!
Of course, I was only 17 at the time.
Apple
PS - that's the one thing you lose when enjoying a movie over and over, year after year. That innocence or 'openness' of seeing it for the first time, not knowing what's going to happen.
And in the Michael sequences of GFII, you really DIDN'T know...because there was no novel to pre-tell the story.