When the charitable arm of UBS launched a $3 million campaign this year to combat human sex trafficking in California, it found that it had to dispel a lot of myths about the problem.

Chief among them was the perception that human trafficking is a problem consisting of young women being forcibly abducted—in other countries.

"People often refer to the movie 'Taken,' where someone is abducted from their bedroom," said Nicole Sebastian, a strategist with the family advisory and philanthropy services group at UBS Financial Services.

While such abductions do happen, the reality is that human sex traffickers operate much more subtly, often approaching their young targets in a friendly manner and then "grooming" them over time before coercing them into the illicit sex trade industry. Moreover, the problem is prevalent in the U.S., with studies indicating 400,000 people—80 percent of them naturally born U.S. citizens—have fallen victim to sex trafficking in the nation.

Many times, children fall victim to human sex trafficking without family, friends and teachers even knowing about it, Sebastian said.

The problem is so pervasive in San Diego that a survey of 20 high schools in 2016 found that all of them had a problem with traffickers trying to recruit their students.

"Children who are trafficked could still be showing up in the classroom," she said.

The prevention and education campaign launched by the UBS Optimus Foundation is centered on the schools of California's San Diego County, which the FBI recently identified as among the 13 regions in the nation with the highest incidences of child sexual exploitation.

The $3 million grant—UBS donated $500,000 and the rest was donated by individuals and family foundations that are clients of the company—will pay for a three-year effort, in collaboration with non-profit groups and law enforcement authorities, to educate children, parents, teachers and school staff about the warning signs to look for when a child is being trafficked, and what to do if a possible victim is identified, according to Optimus CEO Phyllis Costanza.

The program is expected to involve 250,000 students in the county, where, according to a 2016 study of sex trafficking in San Diego by professors at the University of San Diego and Point Loma Nazarene University, the illegal activity was a $810 million industry in 2013, with about 3,500 victims per year. The same study identified criminal gang organizations as the main source of the criminal activity. It also noted that the average age of victims is about 16.

The International Labour Organization (ILO) estimates there are 40.3 million victims of human trafficking globally, which includes those victimized by forced labor and forced marriages. About 75 percent of the victims are female and 25 percent are children under the age of 18, the ILO said.

Part of the reason that UBS focused on the issue is that it has been an issue frequently mentioned by clients in discussion about philanthropic goals, Costanza said. Planning for the campaign started in 2016 and it was formally launched at the beginning of the year, she said.

One of the things the education program stresses is that "you don't need to be moved from one location to another to be trafficked," said Bianca Morales-Egan, senior program manager of human trafficking prevention at Project Concern International (PCI), which, as part of the San Diego Trafficking Prevention Collective, is one of the organizations coordinating with UBS to carry out the campaign.

Morales-Egan stressed that most victims of human trafficking go about their normal lives after having been coerced into the sex business. The study of the San Diego trafficking problem found that only 12 percent of documented cases involved violent coercion, although it noted that this type of coercion may be underreported. More often, the study found, victims were coerced through monetary gifts (74 percent), psychological pressure (57 percent) and through the use of drugs (42 percent).

A focus of the prevention campaign is to alert teachers, parents and students themselves to the telltale signs of someone who is possibly a victim of human sex trafficking.

This includes signs that a student might be depressed or using drugs, Morales-Egan said. Other signs include a student suddenly brandishing tattoos or other "brandings" of a pimp or trafficker, or donning fancy, expensive clothes or purses. With traffickers also preying on victims online, the campaign also tells students and teachers to watch for students who start inappropriate relationships online, she said.

Falling asleep in class, owning more than one phone and being late or absent from school for extended stretches are other warnings signs, those involved in the campaign said.

"Does that person have an older boyfriend that is controlling every move and decision?" Morales-Egan said. "It's usually a multiple of these things, not just one of them, that we see as warning signs."

Beyond prevention, it is hoped the campaign will serve as a model that can be replicated in other high-risk areas of the nation, Costanza said.

"Now that the word is getting out, we're getting interest from a number of other regions," she said.