Secrets dont stay secret very long, especially if you drop them on the enemy. Its become quite common for high teach weapons, like dud smart bombs or crashed high performance aircraft to end up in the hands of the wrong people. During the Vietnam war, Russia got its first close look at new American warplanes and smart bombs. The North Vietnamese made sure the valuable wreckage got to their Chinese and Russian benefactors. The tables were turned a decade later in Afghanistan, where the wreckage of Russias latest weapons made their way to U.S. intelligence analysts. During the 1991 Gulf War, Iraq sold high tech wreckage to the Chinese, and in 1999, the Serbs did the same. But it doesnt have to be a war. Russian warplanes crashing a French air shows have seen valuable pieces of the wreckage disappear, and show up in the laboratories of the highest bidder. In 2001, back in Afghanistan, the Taliban managed to sell some valuable cruise missile and smart bomb wreckage to the Chinese before the Taliban government collapsed. Remember, not all wreckage is just worthless scrap.