Have read posts where people had no problems taking it aboard various ships and others that say it is a really tabu kind of thing. The carry ons go thru the xray machine right in front of you...and that is where I took our Pesi and was requested to open the bag for inspection...which I did with no problems. Honestly, we have never put alcohol in our luggage, so that is why I say it is a crap shoot..for better word..seems some do get caught and others don't. I have no idea how the luggage goes thru xray to determine whether anything is inside. We watched as the luggage was thrown onto a huge roller kind of thing and never saw it again until it arrived in our room. Maybe one of the crew will enlighten us about what happens after your luggage is checked.