Kind of interesting, my gf is an AU on one of my Chase cards, and I can't remember if I took her SSN. But it does not report on hers either.
I added my wife to my Discover IT card (just over a month old) and CK is reporting 3 cards for her, the 2 she has and mine. Discover asked if the AU was my wife and didn't ask for SSN. She also has a Discover Student from 2 months ago.
I have had to put my wife on AU for Citi Hhonors Reserve/CSP. They did not take the SSN so I assume they are not reporting. AMEX is the only card that I have put a SSN into.