I first thought of the Princess cruise, but that is still over a year away. Plus the e-mail has the CCL logo. Jim is likely correct, someone put the wrong distribution list on the e-mail. I've done that before.
It is still a good idea to remind people of the legal requirements. I would not be surprised to learn it is based on people showing up at the pier without the required documents, the ensuing complaints saying it was all Carnival's fault, and someone at Carnival saying "let's do more to communicate the requirements."