bazinga said:
Some people just like the attention.
It's an appalling manifestation of a specific, very dysfunctional personality type.
I used to encounter them all the time at gun shows in the late 90's. The 400 pound Navy SEALs... Treasure hunting has always been a magnet for kooks, fantasists and Water Mitty's. It gives liars an ample opportunity to achieve the emotional rewards liars pursue when they tell their fiction.
The ultimate in loser-personality is the man who tells lies for the sake of lying. Such a man is naturally drawn to situations where he can make fantastic claims and relate grand anecdotes of his own achievement that can't really be 'refuted'.
"Hey, look what I keep finding with my metal detector!" is fertile ground for such losers.
There is real treasure out there with sane and emotionally balanced people looking for it, but you know the liars when you see them.