AMEX is a bit different. They don't have authorized users; they call them additional card members, and the additional card member gets their own number, rather than just their name on your number. When I added my kids as AC, there was no pull at all. Simply asked for identity info including date of birth/social security number/relationship. Kids' files were very thin at the time, but no inquiries showed up on their reports. This was in regards to an acceptance. Don't know if the experience would be the same for a denial.
