diff --git a/ctr_field.module b/ctr_field.module
index 38d3243..08498c3 100644
--- a/ctr_field.module
+++ b/ctr_field.module
@@ -29,7 +29,10 @@ function ctr_field_field_info() {
     'ctr_field' => array(
       'label' => t('CTR Rating'),
       'description' => t('Aggregates a Certified To Rock rating.'),
-      'instance_settings' => array('update_on_cron' => TRUE,),
+      'instance_settings' => array(
+        'update_on_cron' => TRUE,
+        'allow_numeric' => FALSE,
+      ),
       'default_widget' => 'field_ctr_text',
       'default_formatter' => 'field_ctr_simple_rating',
     ),
@@ -50,6 +53,13 @@ function ctr_field_field_instance_settings_form($field, $instance) {
     '#description' => t('Update the Certified To Rock rankings stored every week.'),
   );
 
+  $form['allow_numeric'] = array(
+    '#type' => 'checkbox',
+    '#title' => t('Allow unknown UIDs'),
+    '#default_value' => !empty($settings['allow_numeric']),
+    '#description' => t('Allow saving users not yet in the CTR system'),
+  );
+
   return $form;
 }
 
@@ -61,7 +71,7 @@ function ctr_field_field_instance_settings_form($field, $instance) {
 function ctr_field_field_validate($entity_type, $entity, $field, $instance, $langcode, $items, &$errors) {
   foreach ($items as $delta => $item) {
     if (!empty($item['uid'])) {
-      if (ctr_field_ctr_rating($item['uid']) === FALSE) {
+      if (empty($instance['settings']['allow_numeric']) && ctr_field_ctr_rating($item['uid']) === FALSE) {
         $errors[$field['field_name']][$langcode][$delta][] = array(
           'error' => 'ctr_field_not_found',
           'message' => t('User is unknown to the Certified To Rock service.'),