diff --git a/config.php.example b/config.php.example
index 32cc899..82ee321 100644
--- a/config.php.example
+++ b/config.php.example
@@ -7,6 +7,7 @@ $db_pass = 'dbpassword';
 $db_name = 'dbuser';
 
 # Email subject prefix
+# Will be prepended without change, so should probably end with a space
 $email_subject_prefix = "System name: ";
 
 # Address to use as the sender for reminder emails