As I said we have a lunch box that we take when we travel. It has a manicure set, thermometer for our room, a back scratcher, a corkscrew, a bottler stopper, a swiss army knife, eating utensils, etc. Just any small thing we want for travel. We use the army knife when we buy cheese, salami, etc. to eat in our room. It's always in our checked luggage.
It honestly never occurred to me that it wouldn't be allowed on the ship. It makes some sense but I never thought about it.
That being said, I'm still taking it.