"Brian Gaff" wrote ...
Surely this is the old 'if we had known then, what we know now' syndrome at
work again.

I think failures fall roughly into the following categories, in decending order of
frequency. [Big overlap between 1 and 2]

1. Theoretically should have known the risk, but didn't.
2. /Somebody(ies)/ knew something about the risk - but the right people at the right
time didn't have all the info.
3. Knew the risk fairly accurately and it was deemed acceptable.
4. Came out of the blue.