I visited Hong Kong a year ago. It is famous for its night markets, its abundant partying, and the massive financial powerhouses that make their home here. I did all the tourist things, I partied, I explored, it was great.
A couchsurfing host showed me around the city on a tram. She pointed out masses of ladies in plain clothing sitting around on the sidewalks and in streets. It was a Sunday. This was the "maids day", the one day a week when maids are required not to work.
There were thousands of them, all sitting in groups around the streets and buildings that were closed on the weekends. Groups of street vendors dotted the scene. They appeared when the maids did, a sort of "maid economy", where extremely cheap goods and snacks are sold to the maids on their time off. At night they sleep on the street, and are easily victimized.
The maids have no place to live. During the week they sleep on the floor in a closet, or on a cot in the kitchen of a typical Hong Kong home, and work all day and night, 6 days a week. The little money they make they send home to their family. They are mostly Filipino, mostly illegal immigrants, and as such, they have no rights. And because they have no status here, they also can't get a legal job, leaving them with no other choice to make a living.
There are an estimated 200,000 female domestic workers in Hong Kong (336,000 migrant domestic workers overall), and they are effectively slaves. As many as 56,000 migrant domestic workers here endure forced labor. http://money.cnn.com/2016/03/15/news/hong-kong-forced-labor-... As you might imagine, a large number of these maids are victimized by their "host families".
The really scary thing? I would have had absolutely no clue this was going on if my host hadn't pointed it out to me.