[Zope] Filtering Free E-mail (OT? Was: 20 Million...)

[Jonathan (Listserv Account)]

> TO BE REMOVED FROM FUTURE MAILINGS, SIMPLY REPLY TO THIS
> MESSAGE AND PUT "REMOVE" IN THE SUBJECT.

Maybe a bit off topic, but is it feasible to block access to
mailinglists in general from free e-mail addresses like Hotmail, MSN,
Excite, Yahoo! etc. to avoid these kinda messages?

Or are there simply too many developers and programmers using such a
free e-mail address?

Cya
Jonathan