Originally Posted by
ssk1127
odd thing, though, is that he made it out from the first gate without being forced into customs...my recollection of flying into any American airport from abroad is that you are forced to go through customs due to the gate/terminal design. I can see the confusion if the OP managed to get out of the arriving gate and roam freely through the airport without having to cross customs/immigration.
MEX's Terminal 1 (where MX operates) does not segregate arrivals and departures, but the new Terminal 2 does. Perhaps now that Terminal 2 is operational and segregating arrivals, they are having everyone clear immigration. It's a bit weird, but MEX immigration is usually pretty quick...unlike JFK.