With great wealth being carted out of the caves, some goblins want to get the riches with out having to do the labor. Thieves are fairly common sneaking around in the darkness of the caves. Though many of them don't have the knowledge or skill to navigate the system of tunnels. Many fall into trenches far away from where the miners are working and never make it out. A few have actually been able to steal a few crystals to pawn to jewelers. Other thieves have tried to force a cart worker to hand over the goods, but then they suffer the burden of pushing the heavy weight to the mouth of the cave. Most of the time, each goblin takes a few and runs, and get caught by the BugBear guards to hand over the stollen crystals.