algebraicthunk.net/ blog/ entry/ When good spamfilters go bad.
From: secretary@debian.org
To: Daniel Burrows 
Subject: Acknowledgement for your vote

Spam detection software, running on the system "jester", has
identified this incoming email as possible spam.  The original message
has been attached to this so you can view it (if it isn't spam) or label
similar future email.  If you have any questions, see
the administrator of that system for details.

Content analysis details:   (5.8 points, 5.0 required)

 pts rule name              description
---- ---------------------- --------------------------------------------------
 1.0 NO_REAL_NAME           From: does not include a real name
 1.5 RCVD_NUMERIC_HELO      Received: contains an IP address used for HELO
 1.0 BAYES_60               BODY: Bayesian spam probability is 60 to 80%
                            [score: 0.7536]
 2.3 EMPTY_MESSAGE          Message appears to be empty with no Subject: text

The original message was not completely plain text, and may be unsafe to
open with some email clients; in particular, it may contain a virus,
or confirm that your address can receive spam.  If you wish to view
it, it may be safer to save it to a file and open it with an editor.

(but what if the editor is Emacs and it has a Lisp virus?? ;-) )