First of all how you said they would kidnap Michael force him to work out a deal and release him was the stupidest thing i have ever heard and i literally laughed at that. First of all attempting to kidnap someone like Michael Corleone is already a dumb idea much less releasing him after would only sign your death warrant.
I don't think anyone is suggesting that Roth planned to kidnap Michael, just that they may have told Fredo that was their plan to get him to open the drapes.
Yes, kidnapping and releasing Michael may not have made much sense, but Fredo wasn't exactly the sharpest knife in the drawer - and he was desperate for respect and power - so it's not too far-fetched to think he may have believed that kidnapping Michael, not killing him, was Roth's plan.
I'm not convinced that that is what really happened, but I haven't heard an alternative theory that better explains Fredo's "You guys lied to me" comment on the phone to Ola.
