Waste and environmental concerns have also led to other changes in the main dining rooms. These include menu changes, charging for anyone who orders a third entree (and for every entree after that), and a controversial change that Carnival Brand Ambassador John Heald addressed on his Facebook page.

Some ships even had tuxedo-rental shops for formal night.Related: Carnival Cruise Line shares a passport rule for most portsOn family-friendly cruise lines, including Carnival and Royal Caribbean, formal dress slowly fell out of favor.

Carnival cruise ships offer countless opportunities to eat. Every ship offers a main dining room that serves breakfast and lunch on sea days and dinner every night. These dinners aren't modest: They're multicourse affairs where you can have all the soup,

The cruise line believes that some problems need to be solved by parents, not crew members but also downplays the issue.

A lack of preparation can be costly, so passengers are encouraged to look ahead and leave room in the pre-trip budget for on-board extras.