No. I know some do, but I think it's a minority. (Among commercial
spam-filters used mainly
by corporations, that is. It could be that some of the larger ISPs block SPF
fails outright,
which would skew the picture.)
No ISP I know does that. The false positive rate is much too high,
since publication of a -all record is highly correlated with
assertions that all forwarding is evil, which is of course just wrong.
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