diff --git a/Per-site-switches-syntax.md b/Per-site-switches-syntax.md
index 04b8e2f..1c7349f 100644
--- a/Per-site-switches-syntax.md
+++ b/Per-site-switches-syntax.md
@@ -19,4 +19,10 @@ When switches share a common hostname ancestor, the most specific wins. For exam
     no-popups: example.com on
     no-popups: www.example.com off
 
-and you visit `www.example.com`, the "no popups" switch will be turned off (popup allowed unless blocked by a static filter).
\ No newline at end of file
+and you visit `www.example.com`, the "no popups" switch will be turned off (popup allowed unless blocked by a static filter).
+
+All switches are `off` by default, meaning there is no point in creating an entry such as:
+
+    no-popups: www.example.com off
+
+Unless it is to override a related broader entry for which the switch is `on`
\ No newline at end of file