diff --git a/drafts/human-id-rules.rst b/drafts/human-id-rules.rst
index f28a5a6a..fd20ea81 100644
--- a/drafts/human-id-rules.rst
+++ b/drafts/human-id-rules.rst
@@ -133,7 +133,7 @@ Additional recommendations
 
 Capitalisation
 ~~~~~~~~~~~~~~
-User IDs SHOULD be case-insensitive. This SHOULD be applied based on the 
+The home server SHOULD NOT allow two user IDs that differ only by case. This SHOULD be applied based on the 
 capitalisation rules in the CLDR dataset: http://cldr.unicode.org/
 
 This check SHOULD be applied when the user ID is created, in order to prevent