Step 2: Fake a "boating accident" where you tragically lose the keys for spending those coins
Now your holding is a secret again

It is easier to keep your mouth shut and live a private and modest life than to convince people that you don't own the coin anymore. Just remembered the saying that "prevention is better and cheaper than a cure". Your suggestion sounds nice because those who are aware would be deceived. Maybe I would prefer to stage a fire outbreak in my house and tell them that I lost my keys. I prefer it because people might wonder why you should have your keys on a boat.