"Gravity still works."
(28 July 2007, Czech Republic) A pack of thieves attempted to steal scrap metal from an abandoned factory in Kladno. Unfortunately for them, they selected the steel girders that supported the factory roof. When the roof supports were dismantled, the roof fell, fatally crushing two thieves and injuring three others.
(21 June 2007, Philippines) Three entrepreneurs planned to profit from stolen scrap metal. They entered a former US military complex and approached the prize: an abandoned water tank. Bedazzled by the potential upside, the three threw logic to the wind, and began to cut the metal legs out from under the tank. Guess where it fell? Straight onto the thieves. Their flattened bodies have not yet been identified.
(31 July 1997) Two teens were disassembling an electric tower with wrenches when it toppled to the ground. They apparently wanted to sell its aluminum supports for scrap, but they failed to realize the essential role the aptly named "support" plays in a 160-foot tower. One of the men was crushed by the collapse of the ten-thousand-pound tower, while the other dug himself out from under, a sadder but wiser man. Reference: Associated Press
Darwin notes, "These thieves are playing a deadly game of Jenga! A new target is the lead roofing of ancient churches. This entire category may soon become too common to win further awards, per the Rule of Excellence. See also Barn Demolition."
I would include the following myself.
"Significant Past Incidents
At the Dijon conference the US Nuclear Regulatory Commission (NRC) reported that it is notified of about 200 lost or stolen radioactive sources each year and that since 1983 20 sources had been accidentally melted at steel works and other foundries. According to other sources, 65 meltings have occurred world-wide 9. IAEA says it is aware of 49 meltings world-wide at 1998:"