Index: sites/trunk/wordcamp.org/public_html/wp-content/plugins/wc-post-types/wc-post-types.php
===================================================================
--- sites/trunk/wordcamp.org/public_html/wp-content/plugins/wc-post-types/wc-post-types.php	(revision 2203)
+++ sites/trunk/wordcamp.org/public_html/wp-content/plugins/wc-post-types/wc-post-types.php	(working copy)
@@ -181,17 +181,14 @@
 		// Order by session time
 		if ( 'edit-wcb_session' == $current_screen->id && $query->get( 'orderby' ) == '_wcpt_session_time' ) {
 
-			// Voodoo because of http://core.trac.wordpress.org/ticket/23268
 			$query->set( 'meta_query', array(
 				'relation' => 'OR',
 				array(
 					'key'     => '_wcpt_session_time',
-					'value'   => '',
 					'compare' => 'EXISTS',
 				),
 				array(
 					'key'     => '_wcpt_session_time',
-					'value'   => '',
 					'compare' => 'NOT EXISTS',
 				),
 			) );