--- validateage_with_patch_391884.module	2009-10-24 12:37:12.000000000 +0200
+++ validateage.module	2009-10-24 13:20:22.000000000 +0200
@@ -152,10 +152,16 @@
       $age = _validateage_get_age($birthday);
       $minimum_age = variable_get('validateage_age', '18');
       if ($age < $minimum_age) {
-          if($GLOBALS['user']->uid)
-            form_set_error('', t('Please contact the administrator to change your birthday.'));
+        if($GLOBALS['user']->uid)
+          form_set_error('', t('Please contact the administrator to change your birthday.'));
+        else {
+          if ($age < 1)
+            // User didn't set date at all or chose current year's birthday
+            form_set_error('', t('Please indicate your date of birth.'));              
           else
+            // User is underaged, suggested (not blatant) message reduces probability to trigger lie
             form_set_error('', t(variable_get('validateage_fail_message', 'Sorry, we are unable to accept your registration at this time.')));
+        }
       }
       elseif (_validateage_check_birthday($birthday)) {
         drupal_set_message(t('Happy Birthday!'));