Index: wp-includes/capabilities.php
===================================================================
--- wp-includes/capabilities.php	(revision 15675)
+++ wp-includes/capabilities.php	(working copy)
@@ -735,6 +735,12 @@
 			return true;
 		}
 
+		// If supplied caps contains FALSE or TRUE then return that boolean without checking other caps.
+		if ( in_array( false, $caps, true ) )
+			return false;
+		if ( in_array( true, $caps, true ) )
+			return true;
+
 		// Must have ALL requested caps
 		$capabilities = apply_filters( 'user_has_cap', $this->allcaps, $caps, $args );
 		foreach ( (array) $caps as $cap ) {