Sticky post – save_post bug

I have been trying to unset a sticky post in certain cases, but this cannot be done with wordpress save_post hook. For example :

add_action('save_post', array(&$this, 'check_for_sticky') , 15);
    function check_for_sticky($postID){
        global $wpdb;
           $the_stickys = array();
           $wpdb->query($wpdb->prepare("UPDATE $wpdb->options SET option_value=%s WHERE option_name = %s",serialize($the_stickys),'sticky_posts'));
           return;

On first save it doesn’t work, but on the second one does.