Originally Posted by
whlinder
US DOT rules supersede IATA rules.
The US DOT agreed to the IATA rules with the exception of using the Most significant marketing carrier. Those went in to effect on 24 January 2012. When was the ticket purchased?
Perfectly well stated and cited. Yes, the DOT won't "enforce it" in the sense of issuing fines/fees, but the regulation is effective.
Funny that the OP is now very silent after a very loud rant.