A third person in good faith and without court order may act on the instructions of or otherwise deal with any person purporting to make a transfer or purporting to act in the capacity of a custodian and, in the absence of knowledge, is not responsible for determining: (1) The validity of the purported custodian’s designation; (2) the propriety of, or the authority under sections 45a-557 to 45a-560b, inclusive, for, any act of the purported custodian; (3) the validity or propriety under sections 45a-557 to 45a-560b, inclusive, of any instrument or instructions executed or given either by the person purporting to make a transfer or by the purported custodian; or (4) the propriety of the application of any property of the minor delivered to the purported custodian.