I am wondering if maybe she got off the ship to seek medical attention.
This further leads me to wonder who she was traveling with....friends, parents, a significant other? In whatever the case- did they not notice they were not back on the ship or did they get off the boat with her?
I guess my final question would be that if passenger(s) were not on board for a fairly significant amount of time, isn't there protocol for them to follow, as far as searching rooms/ contacting people? And to give Carnival the benefit of the doubt, maybe the passengers DID contact them and say they were staying on the island due to a medical emergency......but if this were the case, wouldn't they have cleared their cabin right away, not wait until the day of disembarking, because if it were a true emergency, they would not have had a chance to take everything with them. Just curious...