* Are they breaking anti-UCE filters by doing this? (yes)
How? They own example.com.
A) They don't own example.com and, B) this is the crux of the issue. IANA was not granted special privileges by RFC2606 nor do they have any more claim to these domains than Verisign does to unregistered domains or expired domains. Example.dom was placed in the pubic domain by a public and open RFC process. It seems that IANA has violated this process and in so doing exceeded the authority vested in them by their contract with DARPA (and the DOC?).
If UCE happens to contain a forged sender of roble.com, would you consider that even remotely useful in a filter?
Yes. Roble manages several email gateways for companies other than ourselves and we've found that rejecting invalid domains and senders is an indispensable component of spam filtering. Not only is it effective it is also 100% false-positive proof (so far). -- Roger Marquis Roble Systems Consulting http://www.roble.com/