UA669.
Arrived at Kiosk 8 minutes after bag cutoff due to heavy traffic. UA supervisor happily printed a bag tag anyway.
UA>AA. The end.
I had the supervisor check baggage for me at 20 minutes past cutoff on Feb 6th. Regular rep declined to do it, I asked for a supervisor and he gladly did it, though noting it might not make it onto my flight and might arrive a day late. It made the flight.