diff --git a/code/model/SiteTree.php b/code/model/SiteTree.php
index 0ea23c4e..635aeacb 100644
--- a/code/model/SiteTree.php
+++ b/code/model/SiteTree.php
@@ -1576,8 +1576,7 @@ class SiteTree extends DataObject implements PermissionProvider,i18nEntityProvid
 
 		$votes = $this->extend('augmentValidURLSegment');
 		if($votes) {
-			$votes = array_filter((array)$votes, 'is_null');
-			if($votes) return min($votes);
+			return min($votes);
 		}
 		
 		return true;
diff --git a/javascript/SiteTreeURLSegmentField.js b/javascript/SiteTreeURLSegmentField.js
index fc0a183b..55599928 100644
--- a/javascript/SiteTreeURLSegmentField.js
+++ b/javascript/SiteTreeURLSegmentField.js
@@ -5,7 +5,7 @@
 		 * 
 		 * Input validation on the URLSegment field
 		 */
-		$('.field.urlsegment').entwine({
+		$('.field.urlsegment:not(.readonly)').entwine({
 	
 			/**
 			 * Constructor: onmatch