I have done a search on this but couldn't find the answer I was looking for so thought I would ask the highly intelligent BA Board! (yes, I hope ego massage works...

)
I'm connecting AA SEA to SFO onto my return mileage CW SFO-LHR later this month and am wondering whether it is worth a slightly less direct F trip on AA or not (for the same price but extra 60TPs and extra warm nuts).
My only concern is adding an extra connection into the journey, thus increasing my chances of missing my SFO-LHR flight. If my AA flight(s) were delayed would I have any help from them (or BA??) in getting home again?
Thanks in advance
DocS