[PatrickHenry]

we're told that the design inference cannot produce false positives

I'm sure Diamond didn't intend it, but if we rule out any possibility of a false "design" answer, then perhaps we must all become snake worshippers.

[general_re]

Dunno about snake worshippers, but there are small Christian sects that give a very literal meaning to Mark 16:17-18 and Luke 10:19...

17 And these signs shall follow them that believe; In my name shall they cast out devils; they shall speak with new tongues;
18 They shall take up serpents; and if they drink any deadly thing, it shall not hurt them; they shall lay hands on the sick, and they shall recover.
.........
19 Behold, I give unto you power to tread on serpents and scorpions, and over all the power of the enemy: and nothing shall by any means hurt you.

:^)