n=1 but today I got the IAP banner on a domestic flight in WCan... for WestJet. I was looking at a flight-hotel-car bundle when it appeared.
Going back in and checking flight only shows IAP saves about $10 on the domestic flight. the banner was very visible
For fun, checked an upcoming international flight on AC and the AMEX price was about $100 less than google flights/AC but did not indicate the IAP banner.