Wrong. There are innumerable things that Roth/Ola could've told Fredo that he realized were lies immediately after the shooting.

1. That Michael was 'being tough' on negotiations.

2. That there would be something in it for him if he helped out.

3. That whatever he did for them (not necessarily open some bedroom drapes) would be 'good for the family'.

4. Whatever they said would be done with whatever information he provided...would've also been exposed as a lie once the shooting took place.

There's nothing they could've told Fredo that would had him agreeing to open the drapes to Michael's bedroom.

Although Marco's scenario is actually a good one and FAR more logical than the 'Fredo' theory...the question of the drapes is technically unanswerable and therefore ANOTHER flaw in the story for two reasons:

1. After living in that house for at least 4 years...Kay would never dressed for bed and then gotten under the covers without noticing the drapes were wide open.

2. No one, not even Fredo...would've been able to get in the room, open them and leave once Kay was there.

Apple