We just came back from the Grand on 1/28. First of all they do not sell bottles of liquor in the duty free shops onboard until the last night of the cruise. Secondly, Princess says that you cannot bring liquor onboard, however we have done many times and have never had any problems. Any other questions please feel free to e-mail me.
We sailed on the Grand last Spring and had a wonderful time. We brought a small quantity of liquor with us, but they don't care how much you bring. I've heard there is a small uncorking fee if you bring your own bottle of wine to the dinner table, but sometimes it is not enforced. This is a spectacular ship - you will enjoy it.
Joe, I have even seen people with a luggage rack with a case of beer rolling it onto a ship! Princess does not seem to Police passengers with carry on alchol for personal consumption. We as a group of 18 couples all brought one bottle each in our carry-on to share at a private cocktail party. Don't break the liquor state seal and pack a bottle in soft materials and you should have no problem.