Bad message?

[Mike Allen]

To List:
Following is a header excerpt that I get from offensive Spam email:

     X-MailScanner-SpamCheck:
not spam (whitelisted), SpamAssassin (score=3.639, required 2,

Why does it say 'not spam (whitelisted)'.  The source of this email is
not on any 'whitelist' that
I know about.  Furthermore there is no modification of the Subject line
indicating anything
wrong with the email.  I must have made a mistake in 'MailScanner.conf'.

Mike