I brought my PVS-7B night vision gen. three googles with me on cruise last year. It was on the Sapphire Princess leaving from San Francisco and returning to same port, Mexican cruise. If I were flying to destination I don't think I would have taken them, but driving to the port and not having to worry about someone questioning what they were, made the difference for me.
I had fun using them at night. I was up front on the bow and saw a whale right in front of the ship. Could see other ships and lots of birds. The problem was that there is so much light coming off of the ship that it was almost too much light. It was hard to find anywhere were it was completely dark, except for at the bow spot. It was actually a restricted area at night, but I tried it one time.
I showed many passengers and a couple crew members and they all were in shock as to how much can be seen at night. I don't think I would take them again as I was a little concerned about having them out of the country, even though I never took them off the ship.