Re: [email@example.com: Email sent by you blocked because it contains encrypted data.]
> I don't understand, though, why they are concerned about encrypted data
> coming in.
A non-paranoid guess (and I'm one of the more paranoid people you've
met :-) is that their firewall product does virus-scanning on incoming
email, and (quite properly) complains when it can't identify something
well enough to check it. If it is mis-identifying pgp sigs, then the
vendor is way behind the curve, but that's probably all it is...