Sabre is to release its implementation of resolution 302 (way late) to travel agencies on 31 August 2011.

Presumably AA's partition already has it or is getting it around the same time.

As a reminder, U.S. Department of Transportation rules, which apply for itineraries that include a U.S. origin, destination or furthest point, say that the baggage allowance applied at the beginning of the itinerary for the first baggage journey applies throughout the ticketed itinerary, regardless of stopover or subsequent baggage journeys (i.e. you get the same baggage allowance throughout your journey).