Kuki has it right. I've seen that on several cruise lines, no matter how much they try to organize, people get off when they want.
On my Sept. Sea Princess cruise, many people were complaining that they were being called by deck because they were staying in New York, not taking flights. They wanted to get off right away and felt because they were in high priced cabins that they should be able to walk right off.
New York port was a zoo with 6 ships in, many with 2000+ passengers, not a pretty sight at all.
My cabin was on the Plaza deck just beyond the lobby and there were people everywhere in that hall, even though they said to keep it clear.