I suppose it was just a matter of time.

Treasure hunt or terror threat?: "Sidney Reph followed the woman's footprints in the snow, and beneath the tree found a tarp hiding an ammunition box with a combination lock. He told police he ''got away as fast as possible'' because he thought it could be a bomb. Firefighters, police officers and bomb squad technicians secured the area while investigating the mysterious box with ''This is a game'' written on the front. They eventually determined that the box was part of a treasure hunt in which players use coordinates and a Global Positioning System receiver, or GPS unit, to determine where hidden objects are."

I'm surprised it took so long for something like this to happen.