diff --git a/booking.variety_form.inc b/booking.variety_form.inc
index 6aae887..0d3b1eb 100644
--- a/booking.variety_form.inc
+++ b/booking.variety_form.inc
@@ -130,7 +130,7 @@ function booking_variety_session_form_callback($form, &$form_state) {
   //$form['form']['variety-sessions']['booking_feedback_wrapper']['#markup'] = '<div id="booking_feedback_wrapper">Test</div>';
   //return $form['form']['variety-sessions'];
 
-  if (isset($data['booking_nid']) && isset($data['booking_lastname'])) {
+  if (isset($data['booking_nid']) && $data['booking_nid'] != '' && isset($data['booking_lastname']) && $data['booking_lastname'] != '') {
     // Perform lookup on person to make sure it matches someone attending the current event
     $db_and = db_and();
     $db_and->condition('p.booking_eventid', $event->eid, '=');