That's a cute idea! I bet lots of people took pictures of your door. You should send a picture in to Carnival. I bet they'd love to see a door with all their ships you've sailed pasted on it.
I cruised around Christmas a few years ago. One person had covered their door in silver foil, and pasted ribbons going horizontally and vertically to make the door look like one huge Christmas present. There was a big bow at the intersection of the ribbons, and a big card pasted under the bow. It was really adorable.