Thank you! I was always a bit puzzled why the Sun engineers would not verify against the on disk checksum, but it made some sense that in a server setting ECC can be assumed.

By the way, the above "insane" scenario comes from the freenas forums

http://forums.freenas.org/index.php?threads/ecc-vs-non-ecc-r...

and is used to motivate why ZFS should have ECC ram. I am glad to hear that is much less of an issue than it's made out to be.