I asked that question at LHR yesterday and was told no, my later domestic flight out of ORD on AA was not showing in their system (even though I had put in my BAEC number) ... later ended up in an interminable queue to check-in for F at ORD (short staffed due to illness, they said) ... in fact, it was a day for queues for F as I was gently requested to go to another desk, the T5 F area in LHR being chockablock at 9am yesterday