If ya are leaving the country, there will be customs people getting on and coming home. I saw them with a dog sniffing out the bags before they were put on the boat also. Besides that we walked right on the boat without being checked, and by that time all your bags are going on the ship, it was just when we came home they look at your carry on bags and ask ya the common customs questions, like did you buy any fruits or vegetables. Funny thing is we realized later that there were cuban cigars in plain view in the see through mesh bag attached to my kid's stroller and they never noticed.