Returned yesterday from Atl via Mia.
American Airlines looked at negative PCR results And DDJJ on my phone when we got boarding pass checked bags.
Upon arrival at EZE, the pilot announced that someone from Ministry of Health would be checking our DDJJ when we declared, but that never occurred.
The only other time anything was requested was at migraciones in EZE. They asked if we had full vaccines, I said "Yes, do you want to see card?"
"No, not necessary."
As a side note, it was very difficult to find a PCR in Atlanta that would return test results within a guaranteed 3 day period. Most said 2 to 5 days, which wouldn't meet the 72 hr requirement.
Also, most teat centers, free or paid, were totally booked up for a week+. I believe this had to do with coming off New Years holiday when many were closed plus everyone with a sniffle getting a test....