Maybe this is a rhetorical question, but how does UA define a roundtrip? Start and end-point being the same? Is SEA->IAD->ORD->IAD->SEA roundtrip? What about SEA->LAX->NRT->LAX on one pnr and LAX->IAD->SEA on a different pnr? What about RTW? I don't seem to be able to find any defnition on UA's website...