flag.module                 | 35 ++++++++++++++++-------------------
 includes/flag/flag_flag.inc |  2 +-
 2 files changed, 17 insertions(+), 20 deletions(-)

diff --git a/flag.module b/flag.module
index 3881f60..10f6107 100644
--- a/flag.module
+++ b/flag.module
@@ -2284,29 +2284,29 @@ function flag_check_token($token, $entity_id) {
  * @see flag_get_sid()
  */
 function flag_set_sid($uid = NULL, $create = TRUE) {
-  $sids = &drupal_static(__FUNCTION__, array());
-
   if (!isset($uid)) {
     $uid = $GLOBALS['user']->uid;
   }
 
+  // Return 0 for registered users or when Session API is not available.
+  if ($uid || !module_exists('session_api') || !session_api_available()) {
+    return 0;
+  }
+
+  $sid = &drupal_static(__FUNCTION__);
+
   // Set the sid if none has been set yet. If the caller specified to create an
   // sid and we have an invalid one (-1), create it.
-  if (!isset($sids[$uid]) || ($sids[$uid] == -1 && $create)) {
-    if (module_exists('session_api') && session_api_available() && $uid == 0) {
-      // This returns one of the following:
-      // - -1. This indicates that no session exists and none was created.
-      // - A positive integer with the Session ID when it does exist.
-      $sids[$uid] = session_api_get_sid($create);
-    }
-    else {
-      $sids[$uid] = 0;
-    }
+  if (!isset($sid) || ($sid == -1 && $create)) {
+    // This returns one of the following:
+    // - -1. This indicates that no session exists and none was created.
+    // - A positive integer with the Session ID when it does exist.
+    $sid = session_api_get_sid($create);
   }
 
   // Keep the -1 case internal and let the outside world only distinguish two
   // cases: (1) there is an SID; (2) there is no SID (-> 0).
-  return $sids[$uid] == -1 ? 0 : $sids[$uid];
+  return $sid == -1 ? 0 : $sid;
 }
 
 /**
@@ -2318,17 +2318,14 @@ function flag_set_sid($uid = NULL, $create = TRUE) {
  * @param int $uid
  *   (optional) The user ID to return the session ID for. Defaults to the
  *   current user.
- * @param bool $create
- *   (optional) Determines whether a session should be created if it doesn't
- *   exist yet. Defaults to FALSE.
  *
  * @return
  *   The session ID, if the session exists. If not, the return value is 0.
  *
  * @see flag_set_sid()
  */
-function flag_get_sid($uid = NULL, $create = FALSE) {
-  return flag_set_sid($uid, $create);
+function flag_get_sid($uid = NULL) {
+  return flag_set_sid($uid, FALSE);
 }
 
 // ---------------------------------------------------------------------------
@@ -2508,6 +2505,6 @@ function flag_properties_get_flagging_users($entity, array $options, $name, $ent
  * @ingroup callbacks
  */
 function flag_properties_get_user_sid($entity, array $options, $name, $entity_type, $property_info) {
-  $sid =  flag_get_sid($entity->uid, FALSE);
+  $sid =  flag_get_sid($entity->uid);
   return $sid;
 }
diff --git a/includes/flag/flag_flag.inc b/includes/flag/flag_flag.inc
index 071b148..74492e7 100644
--- a/includes/flag/flag_flag.inc
+++ b/includes/flag/flag_flag.inc
@@ -726,7 +726,7 @@ class flag_flag {
       $sid = 0;
     }
     else {
-      $sid = flag_get_sid($uid, TRUE);
+      $sid = flag_set_sid($uid);
       // Anonymous users must always have a session id.
       if ($sid == 0 && $account->uid == 0) {
         $this->errors['session'] = t('Internal error: You are anonymous but you have no session ID.');