In my view, hedid it that way to remove the risk of being misunderstood. He needed to cover himself legally, and as harsh as it sounds, it seems to me that he covered her, too.
he could have recorded the one-on-one discussion about this, with her. and then after expressing clearly what his intent was, given her that note explaining the note legally covers her and him for whatever various benefits each get from him writing it, and her receiving it.
this is why i don’t believe his line about being humane.