The post you referenced TB seems perfectly logical. One question...obviously Fredo had called Tom ahead of Michael's return to Nevada. Wouldn't Tom have been curious about Dredo's detailed knowledge of Roth's escape, and why wouldn't he have told Michael. It is clear when Michael tells Tom to get hold of Fredo to tell him he could return to Nevada, that he was misled, etc., that Tomm had been informed Fredo was the traitor, and in league with Roth. It seems, however Michael and even Tom never connected the dots. Not until Michael tstified did Tom give Roth credit for engineering this so well. Is this another case of Tom not being a good wartime consigliere?

Maybe. Or maybe it is a combination of things. When Michael returned from Cuba he seemed a changed man. He was less analytical, and had a short fuse. He went about insulting Tom about not giving him straight answers, he saw his family was coming apart at the seams. It is possible Michael didn't see the whole picture clearly and it is possible Tom may not have broached the subject as a hypothetical simply because he was afraid Michael would not be receptive to batting around half baked ideas.