I'm beginning to think that nobody involved, actually cares about the solve...Rather, they suffer from vanity.
I suspect there is a good chance he made it all up. Now, if Clara would turn over a $20 bill, that would definitely change my mind.
Gunther wrote that book some 25 years after writing the do-it-yourself divorce article, so it really doesn't carry over to his True readers, as it had been defunct for more than a decade...
And Gunther doesn't seem like the type to make it up... he was a very well-educated Princeton graduate who primarily wrote interesting finance books, notably Zurich Axioms. To do so would be professional suicide... he was quite intelligent and wouldn't take that chnace unless he believed it. The way I understood it, was the FBI was trying to identify Clara, and she got spooked after learning she can still be charged for harboring a fugitive.
Much of the data was deliberately changed by Gunther, as to hide any possible identity, as he agreed, to get the info in the first place. His real notes he corroborated with the FBI and they were trying to ID Clara. And if she made it all up? Possible, but she could not have known about the tie evidence, which fits perfectly.
All of it makes sense, that Cooper realizes the bills are marked, and that in life was a proverbial nobody, yet he is a legend and wants the notoriety, hence contacting Gunther. He cuts it off after learning there is no statute of limitations on skyjacking.
Ask yourself this, why Cooper never came to surface, say, on his deathbed...I mean, this is instant celebrity, and to hide your identity, when the entire world admires you....this is another reason why I believe that LeClair was Cooper, as he supposedly had a heart attack awhile ago and thus didn't have time to come forward.
And how there hasn't been, other than her, a family member coming out after Cooper passed, that it was him (other than Jo). Don't you find that incredibly odd? We are talking about instant stardom, a folk hero... yet nothing....
If Clara was a fraud, she'd have continued her farce, as there was nothing to lose.
Mark, as you finish the book, hopefully you will come to realization as I did, that all of it...all of it, fits like a glove. The only thing I'm holding out hope for, is a relative of Clara comes clean after she dies, presuming she is still alive. Though the book said she didn't have children.