Originally Posted by
bse118
Well - while, AA won't through check bags, it does (somewhat paradoxically) have a policy of protecting missed connections across separate AA or OneWorld tickets. So if something happens to the SEA-DFW flight and your family would miss the DFW-GRU flight, AA's policy would be to rebook them. Not the case if coming in on an unrelated airline.
Note that the current (February, 2019) iteration of AA's protection-on-separate-tickets policy says that it will protect if both tickets are on the same PNR. The new policy is silent about separate AA/oneworld or AA/AA tickets on separate PNRs. It's possible that this is just a typo in the current iteration, but I don't think that there's been anything definitive yet.