The X1 is a drinks package that covers wine (red, white and rose), beer, bottled water and soft drinks, and is only available during the opening times of the buffet and dining restaurants during lunch and dinner. Cost is €11 per person per day, Costa states in its catalogues it is All or None, that means that all persons over 18 y.o. in a cabin must buy the X1 or none at all. Also They did have a offer for a wine package on the first night in the diningroom 1 bottle prosecco, 2 white, 3 red and 10 bottles of water for €86,26. All prices are without the surcharge of 15%. And finally to answer your question Costa clearly states in its terms and condition that any alcohol taken on board will taken from the passenger and returned when the cruise is over.