insert_batch returning -1 when query fails

I'm trying to work with the query builder's insert_batch function. According to the documentation, it should return FALSE on failure. That is not the case.

Try this controller method:

PHP Code:

    public function barf() {
        $data = array(
                array(
                        'title' => 'My title',
                        'name' => 'My Name',
                        'date' => 'My date'
                ),
                array(
                        'title' => 'Another title',
                        'name' => 'Another Name',
                        'date' => 'Another date'
                )
        );
        $retval = $this->db->insert_batch("i_do_not_exist", $data);
        var_dump($retval);
    } 


Seems to me it should probably throw an exception and at the very least it should return false.