Does this not violate local traffic/cabotage rules? To transit a 2nd country between two points within one country is usually a no-no. This violates (when the arguement is extrapolated out to the extreme) protectionist tarriffs guarantering all domestic traffic to carriers that are flagged within that country. (i.e AC does not have the right to fly passengers from LAX to YVR, to CHI, as that is a domestic US itin, which belongs to US flagged carriers.) This is "local traffic" and I don't recall exactly the definition of "cabotage". When UA fleg ORD-GRU-GIG, they were not allowed to pick up any passengers in GRU and take them to GIG, same on the return out of GIG to GRU. Those passengers had to buy a Varig ticket

The exceptions that I am aware of pertain to purchasing (2) separate tickets, priced separately, without thru check in, or thru baggage check ins.

Please correct me where I made my error in logic, as I believe I must have somewhere since you all are doing it.