I asked Crystal about caviar and this is their answer: "We will provide a complimentary individual order to people through room service or in the dining room. There is a charge in the rooms if someone orders for a party."
We ordered caviar several times on our cruise, and it was more than enough for four people. One night we had two guests and we ordered it, and since they did not each much my wife and I made a dinner out of it.
That, and the cheese tray and excellent selection of crackers. There was also fruit and chocolate strawberries.