[quote=Turnbull]
1. Fredo actively conspired with Roth and Ola against his brother's interests, for his own personal gain. ("Johnny Ola bumped into me in Beverly Hills...he said you were being tough on negotiations...but if they could get some help, there'd be something in it for me."[emphasis added.]


But Fredo also said that he thought it would be good for the family.

I think the best explanation for Fredo's role is that they told him they needed the drapes open for some relatively innocuous reason, like that they had to know where Michael was so that they could search his office or some such.