No, that would be evidence for it. I know you are trying to show I am having it both ways, but I am not. Think of the full tree of possibilities: ultimatum/no-ultimatum, bluff/real, rational-refusal/irrational-refusal. If real ultimatum had been issued and Saddam had then refused for irrational reasons, that would be strong evidence against the plan, because that's the situation which is predicted to go well. And that's the situation Punoxysm thought he'd found, but he hadn't.

(Actually, you're the second person today to think I was doing something like that. I mentioned on IRC I had correctly predicted to Gawker in late 2013 that the black-market BMR would soon be busted by law enforcement - as most of its employees would be within two months or so while setting up the successor Utopia black-market - mentioning that among other warning signs, BMR had never mentioned detecting attempts by law enforcement to infiltrate it; someone quoted at me that surely 'absence of evidence is evidence of absence'? Surely if BMR had claimed to be seeing law enforcement infiltration I would consider that evidence for infiltration, so how could I turn around and argue that lack of BMR claims was also evidence for infiltration? Yes, this is a good criticism - in a binary context.

But this was more complex than a binary observation: there were at least 3 possibilities. 1. it could be that law enforcement was not trying to infiltrate at all, 2. it could be they were trying & had failed, or 3. it could be that they were trying & succeeded. BMR's silence was evidence they didn't spot any attacks, so this is evidence that law enforcement was not trying, but it was also evidence for the other proposition that law enforcement was trying & succeeding; a priori, the former was massively improbable because BMR was old and notorious and it's inconceivable LE was not actively trying to bust it, while the latter was quite probable & had just been done to Silk Road. Hence, observing BMR silence pushed the infiltration outcome to a high posterior while the not-trying remained still pretty unlikely.

Of course, for an obscure small marketplace, the reasoning would happen the other way around: because it starts off more likely to be ignored than infiltrated, silence is golden. I'm thinking of titling any writeup "The Pig That Didn't Oink".)