"On Monday, the anonymous blogger Security Crank noticed something interesting: all the U.S. and NATO airstrikes in Afghanistan seemingly kill exactly 30 people every time. How can that be?
"Security Crank documented no less than 12 occasions in which news reports, relying on field commanders' estimates, noted that exactly 30 suspected Taliban were killed in airstrikes and, occasionally, artillery attacks. He said:
'But the much more important point remains: how could we possibly have any idea how the war is going, here or anywhere else, when the bad guys seem only to die in groups of 30? The sheer ubiquity of that number in fatality and casualty counts is astounding, to the point where I don’t even pay attention to a story anymore when they use that magic number 30. It is an indicator either of ignorance or deliberate spin… but no matter the case, whenever you see the number 30 used in reference to the Taliban, you should probably close the tab and move onto something else, because you just won’t get a good sense of what happened there.'
"So, why is it always 30? Do thirty casualties seem like enough to justify a military attack, or few enough to not attract too much attention to an incident?"
http://airamerica.com/news/12-10-2009/us-fudging-casualty-numbers-afghanistan/