I merely gave a trivial (even exhaustive!) enumeration of possible contamination cases that could still have happened (regardless of whether they are targeted against in their protocols), not some novel avenue for contamination that I claim to be "smarter than the scientists" to come up with.
Of course they knew of those contamination possibilities. I didn't say anything about them having missed such basic contamination cases.
What I did (and am) suggesting is that they probably are too confident in their protocols having been executed correctly and being 100% tight with no possibility of error. And that that those avenues of contamination are still a real possibility (protocols to prevent them be damned).
Now, this might not be the case. This might indeed be space travelling RNA-combound and B3 vitamin.
But I'd say that the probability of contamination being the case and someone (on HN or wherever) calling it correctly, is equal to the probability of the samples being contaminated. Which is not that small.
Spotting some novel contamination route they haven't thought off would indeed be very rare and a major feat. But merely been less confident (that they are) in their thoroughness and in their preclusion of contamination, is much easier to claim and be correct while doing so.