We just returned from Hawaii on the Island Princess and had no problem boarding the ship in LA with 2 bottles of scotch in one of our suitcases. Nobody asked and we said nothing. We left the scotch in open view in our cabin, and nothing was said.
In at least two ports, I think Honolulu being one of them, there were signs posted at the security gate as we exited the ship, to the effect that liquor could not be brought back on the ship without being held until we reached our final destination. I do not know if this was enforced.
At most ports, nobody cared, and we brought liquor back on board without difficulty.
On our last night, we had an expensive bottle of wine left in our fridge,so we decided to take it down to the dining room. We paid a corkage fee, $16?, and enjoyed the wine at dinner.
I think bottom line is "do you feel lucky?