diff --git a/xep-0054.xml b/xep-0054.xml
index bcd3e924..05730c2c 100644
--- a/xep-0054.xml
+++ b/xep-0054.xml
@@ -242,7 +242,7 @@
   </vCard>
 </iq>
     ]]></example>
-    <p>If no vCard exists or the user does not exist, the server MUST return a stanza error, which SHOULD &unavailable; or &notfound;.</p>
+    <p>If no vCard exists or the user does not exist, the server MUST return a stanza error, which SHOULD be either &unavailable; or &notfound; (but the server MUST return the same error condition in both cases to help prevent directory harvesting attacks).</p>
     <example caption="No vCard"><![CDATA[
 <iq id='v3'
     to='stpeter@jabber.org/roundabout'