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: The validity of the purported custodian’s designation; The propriety of, or the authority under this subtitle for, any act of the purported custodian; The validity or propriety under this subtitle of any instrument or instructions executed or given either by the person purporting to make a transfer or by the purported custodian; or The propriety of the application of any property of the minor delivered to the purported custodian.