We flew out of MIA on 10/2. Had to show our negative Covid test and the paper authorizing us to enter SXM at the ticket counter. The ticket agent put a red checkmark on our boarding pass. Once we got to our departure gate, there was an announcement that everyone would need to show the Covid and entry paperwork to the AA agent at the gate, before boarding. We stood in line, showed our docs and were told "you already have the red checkmark on your boarding pass, so you are good to go". Maybe the second line was unnecessary. I'm not really sure...