Our forum policy is to provide the official rules for alcohol. The Royal Caribbean Policy
allows them to either confiscate it and let you board, or deny boarding at their discretion. Within the past year we've done two RCI cruises and in both cases I encountered passengers who had personal alcohol confiscated at embarkation, but they were allowed to board.
Please don't try it. Why start your cruise off with a contentious meeting with ship's security in the "naughty" room (that's what they call the room where suspicious luggage is held while they summon you to open your bags).
It is also our policy to close threads on booze once the official policy is provided.