Mormon is not referring to a hypothetical situation. The prophet Samuel the Lamanite had prophesied that men would hide things in the earth but never find them again because of a curse from the Lord (Hel 13:18). This prophecy was fulfilled as recorded by Mormon, ’And these Gadianton robbers, who were among the Lamanites, did infest the land, insomuch that the inhabitants thereof began to hide up their treasures in the earth; and they became slippery, because the Lord had cursed the land, that they could not hold them, nor retain them again’ (Mormon 1:18).
Brigham Young
"We see many of the Elders of Israel desirous of becoming wealthy, and they adopt any course that they think will bring them riches, which to me is as unwise as anything can be--to see men of wisdom, men that seem to have an understanding of the world and of the things of God, searching after minerals throughout these mountains; they traverse the hills, and they dig here and there, and keep digging and picking, and rolling the rocks from morning till night. This chain of mountains has been followed from the north to the south, and its various spurs have been prospected, and what do they find? Just enough to allure them, and to finally lead them from the faith, and at last to make them miserable and poor. Ask the brethren why they do this, and the ready reply will be, ’Is it not my privilege to find a gold mine, or a silver mine, as well as others?’ As far as I am concerned I would say, ’Yes, certainly it is your privilege, if you can find one.’ But do you know how to find such a mine? No, you do not. These treasures that are in the earth are carefully watched, they can be removed from place to place according to the good pleasure of Him who made them and owns them. He has his messengers at his service, and it is just as easy for an angel to remove the minerals from any part of one of these mountains to another, as it is for you and me to walk up and down this hall…
“People do not know it, but I know there is a seal set upon the treasures of earth; men are allowed to go so far and no farther. I have known places where there were treasures in abundance; but could men get them? No. You can read in the Book of Mormon of the ancient Nephites holding their treasures, and of their becoming slippery; so that after they had privately hid their money, on going to the place again, lo and behold it was not there, but was somewhere else, but they knew not where. The people do not understand this; I wish they did, for they would then do as I do, pay attention to the legitimate business that God has given them to perform.” (Journal of Discourses, p. 36-39)