The link below is an example of what you mentioned with Mexican trafficking and yes there are some outrageous things being done out there that we all should find rather disgusting.  Drug cartels can find this attractive because laws and enforcement have not caught with it was they have with drug trafficking.  So they have tended to feel there is less legal risk than getting caught with 400 pounds of cocaine.  For us it's not always that easy to tell when a provider is doing it by choice or by coercion.  Some coerced providers learn to be very good actors because they know it's bad for their business if clients think they are sex slaves.  When business gets bad they know their traffickers/pimps take it out on them.  This is one reason it is best for us to focus on known reputable providers who we know do it by choice and enjoy the full benefits of the profession themselves.  Those such as the lovely independent ladies who participate on this board for example.  

My concern is that the laws tend to go from one extreme to another and if this continues, which it likely will, ever more laws may be passed.  All you need is for there to be a major government scandal involving trafficking that causes government embarrassment in Washington and the laws will fly out the door.  Just look at the housing bubble and the laws and regulations that came from that, anything to deflect the blame form themselves.  If/when that happens there will be the temptation in some circles to try and start moving stronger laws into application of other areas of the hobby that involve fully willing participants.  Hopefully a temptation that will not take root or fly in the courts, but still a temptation.  One big grey area is the K-girl area where some will argue that it is a form of trafficking and others that it is not.  I don't even want to open that can of worms again on this board other than to point it out as a possible area of concern.  Then it can move to other agencies and maybe even independents.  

If you do come across a provider where things just don't seem right and it looks to be a trafficking, sex slave, type situation there are things you can do without having to call LE.  There is an anti-trafficking hotline service called the National Human Trafficking Resource Center.  They have a national, toll-free hotline available to answer calls from anywhere in the country, 24 hours a day, 7 days a week, every day of the year.

This is a program of Polaris Project (www.polarisproject.org) which is a non-profit, non-governmental organization working exclusively on the issue of human trafficking.  They are not a government entity, law enforcement, or an immigration authority.  Their number is 888-3737-888 and would be a reasonable place to report forced human trafficking.  

That's a good question.  I have seen some where that seems to be the case and other where it seemed less likely.  I have gotten to the place where I avoid many of those.  It's not just the possible HT aspect, but also the volume, "revolving door", aspect.