I have never had a problem bringing any beverage on board - and I always have packed it in my luggage. In terms of going through bags - of course it's the same as an airplane. In terms of going through your belongings in your room - of course some of the cabin attendants do - however it's not to see if you have liquor...it's to see what other fun things you brought! Take the opportunity to wear all your jewellry if you bring it with you and USE THAT SAFE for any items you do not want your cabin attendant going through.