Clarify that the updatedn should not be same as the rootdn.

doc/man/man5/slapd.conf.5

@@ -1208,6 +1208,10 @@ The
 parameter specifies the DN in the consumer site
 which is allowed to make changes to the replica.
 The DN should have read/write access to the replica database.
+Generally, this DN
+.I should not
+be the same as the
+.BR rootdn .
 A
 .B bindmethod
 of 
@@ -1247,7 +1251,10 @@ This option is only applicable in a slave
 It specifies the DN permitted to update (subject to access controls)
 the replica (typically, this is the DN
 .BR slurpd (8)
-binds to update the replica).
+binds to update the replica).  Generally, this DN
+.I should not
+be the same as the
+.BR rootdn .
 .TP
 .B updateref <url>
 Specify the referral to pass back when