If you find something valuable, and you tell people you found it, you will be bombarded by demands from many different people who claim to be the legal owner. They lost it, they have claim to the property where you found it, their grandpa owned it, their uncle buried it - these people just come out of the woodwork, and they will drive you nuts.
Most treasure hunters keep their mouths shut when they find something valuable because they know the headaches publicity will bring.
The honorable thing to do is to quietly have it appraised and pay taxes on your profit.
Of course, if you pay taxes on your finds you can also take deductions on the money you spend on detectors, the cost to travel to hunt sites, etc, etc. Your hobby becomes a business. THAT can be a headache, too.
Most veteran treasure hunters just keep their mouths shut.
