I read a brief post by someone why made decent money smuggling drugs in a prop plane across the US. He only did it a couple of times (didn't let greed take over). He didn't go into details, but I imagine some people feel like they can mitigate the risk, or don't have much to lose.
I remember reading that you have 2 years max to make money and get out before your guaranteed to get busted. It was a fun book. Personally I wouldn't recommend the lifestyle choice.
