Comments:

E.4 - nicknames or group names should not be viewed as spam simply because the sender's mail information is visible only in the email header. This should apply to valid and legitimate email groups, ie, Yahoogroups, etc. However, if one receives such mail, it is never unsolicited as one must voluntarily subscribe to such services. Nicknames can be assigned thru one's personal address book for convenience. The original information should still be accessible through the mail headers however so in essence it is not a spoofed email address.