Victims are transported via airplane (here's what to do if you see something suspicious on a flight) and train, and often kept in hotel rooms. This is where meeting managers—and the hotels they use—enter the picture.

“At first, when you talk to hotels, they’re shocked and will say, ‘This doesn’t happen in my property, we are a resort,’ or ‘we’re a five-star hotel,’” says Kimberly Ritter, senior account manager/trafficking initiative coordinator, Nix Conference and Meeting Management, St. Louis. "You don’t have to be in a motel to have a girl brought to your room.”

When she speaks with a hotel and gets resistance, Ritter, who has become a leading advocate for this issue, will sometimes go to Backpage.com, a Craigslist–style Web site that includes a section for finding an escort, and research not the girls, but the hotel settings they are in. "I’ve traveled so much that I can recognize a landmark outside the window, or a certain chain’s bedspreads or throws,” she says. She has printed out the listings and brought the photos straight to the hotel general managers. “I had to prove it because no one believed it.”

Kimberly Ritter being presented with the 2012 Director’s
Community Leadership Award by Dean C. Bryant, special
agent in charge of the FBI St. Louis Division, for her work
combatting human trafficking

“This is not a moral thing, it’s illegal," says Jennifer Silberman, vice president, corporate responsibility, at Hilton Worldwide. “At the end of the day, you need to make sure your hotel is not an accomplice. Knowing and not doing something about it puts the hotel at risk.

"There is no gray in this, it’s black and white—it’s sex with a minor."