Those days are over. With computer systems they know exactly who is on the ship and who is not supposed to be on the ship.Funny story. Many moons ago a friend and I were invited by his lady and her best friend to go to a Bon Voyage party as they were going on a one week carribbean cruise leaving from Dodge island. They have those for a couple hours before the ship departs. Music and partying for people wishing their friends and family a good voyage..
We all got toasted and retired to the girls cabin where they had another bottle of something and continued drinking oblivious to the load speaker announcement that the ship was soon leaving port
.Next thing you know we all saw the dock going by through a porthole as the ship was heading out to sea with me and my buddy as unintentional stowaways.
Long story short they took us to see the Captain who invited us to go along for the ride for free and be flown back from their first port of call (also free)if we wanted to.
Had to work the next morning so we declined and they had a pilot ship come out and get us at the entrance to Government cut.