function wpsc_get_expired_visitor_ids() {

        if ( ! _wpsc_visitor_database_ready() ) {
             return array();
}

global $wpdb;
       $sql = 'SELECT id FROM ' . $wpdb->wpsc_visitors . ' WHERE expires IS NOT NULL AND expires <  NOW() AND id <> ' . WPSC_BOT_VISITOR_ID . ' ORDER BY exp
       $visitor_ids = $wpdb->get_col( $sql, 0 );
       $visitor_ids = array_map( 'intval', $visitor_ids );
    return $visitor_ids;
}