Just curious, where and when did you see "it"
with your own eyes 
?
Just realized that you had replied to my post. Sorry for the lateness. Anyway, it is a VERY, very long story so I will try and give you the condensed version.
I lived in China for 8 years, in a small town not too far from Shanghai. (Our family had been sent there because my father's boss gave him an incredibly job opportunity that was branched in China) I hung out at my father's office frequently afterschool. I was very close to one of his employees - her name was Xiao Feng. She was absolutely beautiful, and she had such a warm heart too. My parents would always get her to babysit me & my brother when they had to go away on business trips. She took great care of us, and even though she was from a very poor family, she refused to be paid for babysitting us, no matter how much my parents insisted. She had strange scars all over her body though, and whenever I asked she said that it was from dropping stuff when she was cooking. I was very young then, so I believed her.
4 years after working at my father's company, she had to leave for the Shenzhen countryside because her mother was very, very sick. Our family insisted on paying for the healthcare, and she agreed, but after she left from Shenzhen she was no where to be found... She never contacted us, nobody ever picked up the number she gave us. I still don't know where she is, and what she's up to, but I really miss her.
2 years ago, when my parents finally decided I was "old enough," they decided to tell me the truth about her. Xiao Feng was an ex-prostitute who like many other young Chinese women was tricked into the prostitution business. The "pimps" took advantage of how naive and gullible they were, and promised them high-figure salaries working at a "massage parlor." They would supply them with food, housing and just about everything if they agreed. Of course it was all lies - they were treated horribly, they were beaten up, tied and raped if they didn't make enough money. The only thing the pimps really paid for was makeup and revealing clothing. They were NEVER given any form of contraception and weren't allowed to insist that their clients use condoms. (The pill was also unheard of to them... Sex education was strictly forbidden back then.) So they were considered lucky if their clients offered to wear condoms. Most of the women stayed in the business, because they needed the meager salary... Xiao Feng couldn't stand it though - she ran one night, far, far away to Suzhou where she had heard had a new & developing zone with far more job opportunities. She was right to go there.
But yes... Xiao Feng learned a lot from 2 years as a prostitute. She met a few friends, and the more highly-demanded prostitutes were let in on some more secrets of the business. (Heck, some of the prostitutes were assigned management/client-hunting positions that would mean no more prostitution for them once and for all. I think that is what motivated some of them to stay in the business too.) ALL of these pimp's actions weren't just limited to opening prostitution parlors. Their main revenue actually came from counterfeit goods, only through this revenue were they able to afford the fancy facade and interior of the parlors. The counterfeit branch in Shenzhen, Shanghai and Beijing made them SO much money. The pimps reaped millions and millions from the trade. They also used the money to bribe the police not to shut their parlors down and keep quiet about them. The police were INCREDIBLY corrupt then (still are, really). Of course, the pimps were also infamously known for their links to a gangster group of hitmen so no one really dared to file complaints about them.
Many people that live in China today (including expatriates) are well aware of this problem. They just choose to ignore it - I don't even know why. Some people just don't care. Of course, several others are aware of it and they do their best to employ as many girls that have escaped from the prostitution business. They're not too hard to identify.
Nobody deserves to go through what any of these girls did, and still do...
Like tigerrogue's experience, some of this stuff has to be witnessed on a local basis. Nobody's gonna tell BBC a story that could get them shot, and BBC isn't gonna report a story unless you have video footage, pictures, witnesses that dare to speak about it... Of course, I'm not in China anymore, and I don't think any of these pimps read TFS... So I'm pretty much safe, at least I hope I am!
Agh, I cry everytime I write about this
