Adding a AU after an application does not impact the person's being added inquiries on their CAR.
Do they ask for the Social of the AU? Without that information they will not add hard pulls.
I added my wife to my citi and discover card as a AU and both report on her credit report. Neither posted an Hard inq.
Although it has been about two years since, when I apped for an Amex I remember in the application itself it only asked for the name of the AU I wished to add. Wife never had a HP. When I apped for Chase in February of this year, same thing, just asked for name and no HP for her.