You’re absolutely right about whose responsibility it was to check the card. However we were required to submit copies of our vaccination records during the pre booking process. I accidentally submitted a copy of my first shot twice stead of a copy of shot 1 and 2. Within an hour I received a call from RCL advising me of my mistake which I corrected immediately. My boarding was then approved and I was good to go. My husband provided copies of shot 1 and 2, shot 1 had the batch number shot 2 did not but RCL accepted it and approved his boarding. We have print outs from RCL stating our records were approved and we were good to board the ship. . When we got to the pier we were told we needed the batch number.