The 'human trafficking' thing is largely a tempest in a teapot. I used to have some friends who were involved in the 'Asian massage parlor' trade in the Seattle area. Mostly SE Asian immigrants with very poor English skills and very limited economic opportunities. There was no 'trafficking' i.e. slavery. The girls were free to come and go as they chose, and they often did. If there had been 'trafficking' I would have turned them in to police myself.
Washington state passed an anti-trafficking law in 2003 and didn't get the first conviction until late 2009.
State's human trafficking law fails to snag a conviction - seattlepi.com
The first conviction was of a 19-yr-old pimp and gang member named Deshawn "Cash Money" Clark. Hardly the image of international intrigue and sophisticated organized crime that crusaders push.
It's pretty simple--vice cops and anti prostitution crusaders know that there is not much public support for going after consenting adults, so they come up with the trafficking canard as a smokescreen.