^Yeah. If it were as easy as Myasishchev proposes for a government to control crime in a small urban area, then every slum in the world would be crime-free. Evidence shows the opposite to be the case.
Remember, this film is an allegory for things that are really happening in South Africa, that have been happening for decades. The location where D9 was filmed was a real slum whose people had been forcibly relocated just like the aliens in the film. They didn't dress it up to look that filthy and garbage-ridden -- it was like that when they got there. Clearly it was not a well-regulated area. Places like that are the kind of places where you'd expect to see black markets dealing in guns, drugs, and other harmful things.
Remember, this film is an allegory for things that are really happening in South Africa, that have been happening for decades. The location where D9 was filmed was a real slum whose people had been forcibly relocated just like the aliens in the film. They didn't dress it up to look that filthy and garbage-ridden -- it was like that when they got there. Clearly it was not a well-regulated area. Places like that are the kind of places where you'd expect to see black markets dealing in guns, drugs, and other harmful things.