Since we are vaccinated, and no serious symptoms, testing would not change our behavior, stay home and isolate.
If we got sicker, I guess we would go get tested to eliminate/confirm covid.
As for the population stats, if I knew there was 0 covid on the ship, I'd feel it's probably not covid. If I knew 66 people caught covid on the ship, I'd believe it's very likely I was exposed.
You can be on a plane and not be exposed, and you can be on a cruise ship and not be exposed.
For example Carnival Vista just had an outbreak of 27 cases
26 were crew and 1 passenger, on a ship of total capacity of ~5,400
If everyone on the ship was exposed, they would have a LOT more than 27 cases.
https://www.usatoday.com/story/trav...-27-positive-cases-carnival-vista/8105767002/