The Tomb of Gnasher III - King of all the Goblin Undergrounds

From the back of the book: The party of player characters may well have heard of Gnasher IIIs tomb (in fact the GM should make sure of it) and the legend that it contains the un-looted treasure of his burial goods. No matter, this is of small importance. The fact that it is undisturbed and waiting to be taken should awaken the greedy instinct of dungeon looters. Somewhere though, in the backs of their minds a small voice may be saying, but why is it un-looted?