On the departure from MEX to SEA on 6 May, they did ask questions. Had several folks with orange vest on that was walking about the gate area asking folks if they had the sticker on their passport if you didn't already have one, they simply asked some basic questions of weather you had control of your luggage, did any one ask you to carry something. In general nothing really a big deal at all. (IMHO)

BTW, with regard to "upgrades" the 738 that they flew that day from MEX to SEA, there was a total of 6 seats open up front when everyone was done boarding. They brought up one person, leaving the 5 other seats up front empty. I was in 3B and 3A was left empty the entire flight. So I don't know what the process is for upgrades for AM, but find it hard to believe there was not a single person with a Delta SM account that would have been able to upgrade. But then again, don't know what they use and as far as I know AM does not have a public viewing of their upgrade list (like Delta, etc have in their App)