I hear you. But since it wasn’t their land, it’s a state park I think, they couldn’t dig without permission. Trying to dig without permission is just asking for trouble. I’m sure they weighed all this.
I think they got $crewed too, but just like in the UK, if you find buried treasure - especially on public land - you better report it.
There was a case a couple of years ago, where a guy found some ancient Viking gold jewelry and tried to sell it privately. He had to serve some time.
But you’re not supposed to do it the stupid way.