I am looking to do the LAX-ORD-DUB MR in November. I notice it is the same price for me to do ORD-SAN-LAX on the return as it would be to just do ORD-LAX.

I live in SAN and it is expensive to do the whole MR from SAN, but I could easily Amtrak up for the start and just end back in SAN if I skipped the last segment. Would this invalidate any of the miles I did complete?

I certainly would let AA know I was not going to fly that last segment after returning to SAN so they don't evacuate the airport looking for a "missing/suspicious" passenger.

Thanks!

BTW, I'm only asking cuz that last segment gets into LAX too late to take the last train of the day back to SAN and I'd have to stay over or drive up, pay for gas, parking, etc.