I would not touch something which I don't have a moral and legal right to do so. This emanates from my faith. Those slumbers should be given recognition and an incentive for their honesty. It is incredible that they returned the gold judging by its value. The rewards for dishonesty are short term and transient while honesty and integrity pay in dividends.
It is hard to know what we would do in such a situation, but like Alex pointed out...it would be quite hard to just "cash in" a gold bar. I mean maybe you could do it through the Black Market or something but I wouldn't know how to do something like that. I guess it would come back to bite you in the butt somewhere along the way.
