Originally Posted by mustachepete
Originally Posted by Evita
1. who else had the motive and incentive to open the drapes

I'm confused by the use of "motive and incentive." Anyone who was assisting Roth would have motive and incentive to open the drapes. We don't know who that might be, but it seems unlikely that Fredo was the only traitor involved in the hit
Originally Posted by Turnbull
Nowhere in the film is it shown that Fredo opened the drapes. But, as we saw, Kay was surprised that the drapes were opened, and the shooters fired at Michael through the window. My conclusion is that, with thousands of people on Michael's estate for Anthony's party, Rocco would have assured that guards were posted around Michael's home to prevent people wandering in to take a look inside, or perhaps to lift a "souvenir." But Fredo would have been allowed in. And Fredo had motivation because he was cooperating with Ola against his brother
Sure thing “I too can't see anyone else allowed into their home let alone” -- their bedroom and “anyone involved in Corleone security” would really have no business? being inside their Boss' bedroom So my take too, that leaves only Fredo

Extracts:
Originally Posted by mustachepete
If you mean "opportunity," anyone involved in Corleone security might have access to the drapes, including Rocco who is often listed as a possible traitor in the family
You are right Pete Rocco was discussed as a possible traitor and if my memory serves me right, was disregarded because if there was any suspicion at all, Rocco would be sleeping with the fishes when Michael returned from Havana, certainly not continuing to guard the lives of Michael, Michael's wife and their children -- the future of this family

Besides no way! Rocco knew what happened to Paulie – extermination!

Originally Posted by mustachepete
What is Fredo's failure, anyway? He tells Michael he never met Roth or Ola, then lets slip that he's been with Ola in Havana. What else?
Among others -
  • "He tells Michael he never met Roth or Ola, then lets slip that he's been with Ola in Havana" [you mean Superman?!]
  • Fredo's “little help” -- for “something in it for me -- on my own”
  • Fredo kept the Senate hearing secret, from Michael
  • Fredo withheld the information he knew, from Michael