The only ambiguity that creates is whether a child under 5 must be vaccinated. It does not create any ambiguity whatsoever about testing required of a child who IS fully vaccinated. If a child is fully vaccinated, then the "what to do if your child isn't fully vaccinated" section obviously doesn't apply to them.
If a section says "if your son is under 3, he must wear a blue shirt," I'm not going to wonder if that rule applies to my under-3 daughter because it clearly says "son."
The system is extremely clear, I don't care what people are being told on the phone by poorly-trained Inspire agents in an environment when policy is constantly changing and communication is imperfect at best. I've done three COVID cruises with kids 7, 4, and 2 and it's not nearly as complicated as everyone is making it seem. People in this thread and others are doing a disservice to new cruisers by giving them anxiety and making them worry needlessly.
15 days comes up, you log into Safe Passage, you load everyone's vaccine cards. 2 days later you're either Clear to Arrive or you're not. Even in this nightmare "worst case scenario" where the vaccine card is rejected...... SO WHAT!? Just order the PCR test instead of the antigen test. Who cares? You're literally no worse off. The Safe Passage site holds your hand through every single step. There's no possible way you can mess it up, especially if you order all of your tests right through them.