http://wikileaks.org/cable/2006/08/06PHNOMPENH1406.html

Typically shrouded behind legitimate
businesses, Phnom Penh’s sex establishments catering to the
Chinese operate relatively discretely. Generally, Chinese
men come to Phnom Penh for business reasons, not for the
purpose of sex tourism. Chinese clientele refrain from the
low-end brothels used by average Cambodians, preferring
karaoke bars and massage parlors that cater to the Chinese.
Some of these establishments have girls suspected of being
trafficked from Vietnam and increasingly from China; numbers
of underage girls present are hard to estimate, but girls as
young as 14-15 years of age are not uncommon. Debt bondage
draws some Chinese sex workers to Cambodia.