snedmail防中文垃圾邮件，能够检测出，但是还能收到该邮件

老菜小笠

我在做sendmail＋spamassassin＋mimedefang的时候，遇到不能拦截中文垃圾邮件的问题。自己给自己发送了一封标题为发票的垃圾邮件，结果邮件还能收到。底下显示为相关信息
Spam detection software, running on the system "node103.cluster.com", 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 preview:  12312 三等分 -- Open WebMail Project (http://openwebmail.org)
   [...]
Content analysis details:   (8.8 points, 5.0 required)
pts rule name              description
---- ---------------------- --------------------------------------------------
-1.4 ALL_TRUSTED            Passed through trusted hosts only via SMTP
0.1 CN_SUBJECT_6           Subject contains "发票"
3.2 CHARSET_FARAWAY_HEADER A foreign language charset used in headers
0.1 CN_BODY_3              BODY: Body contains "发票"
2.5 MIME_CHARSET_FARAWAY   MIME character set indicates foreign language
4.4 AWL                    AWL: From: address is in the auto white-list

从上面看spam已经给他评分了，但不能阻止他发信，为什么呢？