Boarding Aeromexico at San Francisco was interesting. We are in Group 1 but the only signs were for 2 through 5. We happened to be behind an American woman who travels on the airline frequently, and she confidently marched up to the counter with us behind her and before we knew it we were aboard and seated with our carry-ons stowed.
After an agreeable flight on an Aeromexico 737 SFO-MEX, we've found the airport fairly smooth. Everybody has been polite and even friendly. We got through Immigration quickly, then Customs.
We found the entry to the gate for our onward flight to Buenos Aires with minimal confusion.
The security person was polite, friendly, and patient with people unfamiliar with their procedures. We had to take our iOad Mini, iPhone and iPod out and put them in a bin before walking through the metal detector with our shoes on. The employee even said "Have a nice flight" as we left the checkpoint.
We then found our way to the Aeromexico lounge, a big barn of a place, and we're relaxing here before boarding our overnight flight to EZE.
We have visas for Argentina good through 2020 so that shouldn't present a hurdle to us. We're a little surprised we've gotten this far without any airline employees wanting to check them. Fingers crossed...