But Turnbull, remember the scene where Fredo gets the late night phone call from Johnny Ola. He's pretty miffed at Johnny, telling him, "You guys lied to me." He pretty much breaks his clandestine ties with him right there, not giving him (and not offering to uncover) the further information Johnny requests.

This indicates to me that Fredo did not know he was colluding in a plot to murder his own brother, and that he was angry that he had been misled. Yes, he had deep resentment and yes, he was willing to double-cross Michael or place him in a victim's position in order to build himself up; but I believe his ambitions did not extend to fratricide.

I think there were a number of excuses Johnny Ola could have given to Fredo for opening the drapes and that Fredo, not being very savvy, would have believed them. These would have centred on Ola's men needing to "see" when Michael was in that room. Maybe Johnny told Fredo that a kidnapping was planned (as an early draft of the script indicates) and that the bedroom was the best "capture point" (on the ground floor, closest to the woods, etc.) Perhaps he said that they wanted to scare Michael by holding Kay at gunpoint or something, until Michael agreed to Roth's demands. Maybe they had to plant recording devices in every room with a telephone and they needed to "see" when the room was empty so they wouldn't get caught.

Fredo had a love-resentment relationship with Michael. When the two of them have drinks the afternoon Fredo arrives in Havana, one can see that Fredo basks in the closeness and rapport he has with his brother; it's apparent in his plaintive question, "Why didn't we do this before?" Just going as far as he did with Ola has left him guilt-ridden. As much as Fredo also longs for respect, I don't see him going to the lengths of murder to obtain it.