Cruise ships are floating resorts where the staff can sometimes seem obsessive about making sure you have a great time and the word "no" is seldom heard. However, it is important to remember the rules. Cruise lines have strict guidelines about what you can do or say without getting kicked off of one of their cruises. While most of these rules and regulations for what you can't do on a cruise ship may seem obvious, others can seem absurd.
The good news is that most of these prohibitions are rules that are very easy to follow. Most folks never really have to consider what they can't do on a cruise since there are so many activities to do, new friends to make, ports to explore, and public parts of the ship waiting for you to discover them.
The key here is to trust your intuition. If it seems like you probably shouldn't be doing something - even if it is completely legal back home - you probably shouldn't try it at sea.
Cruising is a unique space sometimes but these rules are to keep cruise guests safe and allow the crew to do their jobs as effectively and efficiently as possible.