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 any of the following:

  (a) The validity of the purported custodian’s designation.

  (b) The propriety of, or the authority under this act for, an act of the purported custodian.

  (c) The validity or propriety under this act of an instrument executed or given either by the person purporting to make a transfer or by the purported custodian.

  (d) The propriety of the application of property of the minor delivered to the purported custodian.