On a cruise ship, what happens if you don't attend the mandatory safety drill?

Perhaps you should ask the passengers and/or ...

You can be debarked from the ship with no refund for not following mandatory directions . It's happened.

The crew check all the cabins and common areas to direct people to the boat drill. Then they take attendance. If you don't show, they will call and/or go by your cabin later for a remedial lesson. If you refuse, yes, you can be debarked with no refund. I was once on a pre-maiden-voyage sailing, moving Holland America Line's Noordam from a marketing event in NY to its first commercial sailing from Boston. Every "passenger" on the vessel worked for the cruise line (either as an employee or vendor) and had been on many, many sailings. Most had designed or built or marketed the vessel and knew it inside out. Every single one of us, including the president of the company, did the boat drill.

The initial safety drill is not the only drills you will find on cruise ships.  On Holland America we have an attacking pirates drill when entering areas were pirate activities have been reported such as the Indian Ocean.The answer to your question is as others have stated, you will be debarked.  You don't want to be the person who keeps everyone at their drill stations while the crew looks for you.

Since the Costa Concordia incident there have been changes in the cruise industry where cruise ships are now required to have the mandatory safety drill prior to the ship leaving port on embarkation day. Attendance is taken at the muster stations and if you do not attend the drill then the ship's crew have the right to debark you from the ship without any refunds.