Lots of commenters sound like they’ve watched a good amount of breadtube or have read Sex at the Margins by Laura Maria Agustin, which does an amazing job of demystifying a lot of the existing assumptions about migrants and trafficking. This based book does a lot of good work tackling a particularly touchy subject by actually interviewing the people involved and humanizing them rather than use them as faceless othered political fodder
In addition to the obvious strategy of continuing to be a good client, here's some more things clients can do to help, with varying degrees of commitment involved:
Oh yeah, it's libertarian bullshit for sure. This is her book: https://www.amazon.com/Sex-Margins-Migration-Markets-Industry/dp/1842778609/ref=sr_1_1?ie=UTF8&qid=1481336883&sr=8-1&keywords=laura+agustin
EDIT: jesus fuck I am screaming about this Amazon review of it:
> The whole notion of "migrants" is deeply class biased; no one ever called an Indian bond trader working in New York a migrant. But he or she has travelled for the same reasons as dishwashers, nannies, and strippers - to make money, for sure, but also to see the world, or escape suffocating origins.
...what do you even say to something like this? What did I just read? Obviously there are class differences between bond traders and strippers and it would be INSANE to ignore the differences. The fuck are these people smoking?
EDIT2 (SORRY I JUST CAN'T GET OVER THESE REVIEWS): Another reviewer goes on to compare her to Emma Goldman and calls the book a classic! I'm just gonna leave this here (Goldman was decidedly anti-state interference in prostitution buuuttt she still wants it eradicated/calls it a social evil, etc): https://www.marxists.org/reference/archive/goldman/works/1910/traffic-women.htm
You might want to read Sex at the Margins by Laura María Agustín (I mention this a lot). It doesn't focus on the US, but it takes another perspective of sex trafficking. As I (roughly) remember it, there are a number of women who say they have crossed a country's border to do sex work, and the person or organization who helped them cross withholds their passport until they make X amount of money, which is not what they agreed on. This is coercive, but the women in the book have more agency and freedom than the US media would have you believe, IE they knew they would be doing sex work, they still make money to send home to their families, and they are still able to go home if they want to leave the situation. These women identify as migrant workers, not "trafficking victims". I definitely recommend reading the book, however Laura María Agustín's blog also has lots of additional ideas and information.
Here is a good starter book, for when you decide you want to hear the voices of migrant sex workers (and sometimes victims of trafficking):
https://www.amazon.com/Sex-Margins-Migration-Markets-Industry/dp/1842778609