Subject headers constructed by rmail-forward

[Glenn Morris <gmorris+mail@ast.cam.ac.uk>]

When rmail-forward constructs a subject line for a forwarded message,
it produces something like:

Subject: [original_from_address: original subject]

I think it ought not to include the email address of the original
sender in the subject header. The reason is that this possibility
seems to be overlooked by some anti-spam-harvester devices.

For example, that of mail.gnu.org, http://mail.gnu.org/spam.html.
Email addresses appearing in message *bodies* are protected, as are
those appearing in From: headers, but any in the Subject: header are
left intact. For example,
http://mail.gnu.org/archive/html/emacs-devel/2003-04/msg00024.html.

Maybe such schemes should be improved, but I would still prefer not to
have email addresses added to Subject: lines. My personal preference
would be for a new subject header of the form:

Subject: Fwd: original subject

WDYT?