And the bottles of liquor you buy duty free from the ship's shops are held for you until last night of cruise, so you cannot drink that either.
I always bring a dozen cans of beer on board at each port and bottle or two of wine, no problems so far, I declare it to security and always check with them on going off ship if it is OK to bring it back on. BUT I also purchase plenty on board from the bars and restaurant too.!!
Best wishes from Australia.