90% of the time that is true. But there are abductions that occur. And sometimes they are people that have families/friends who will look for them:
http://abcnews.go.com/Primetime/story?id=1596778&page=1
Abducted From Her Own Driveway, Teen Says
Debbie's story is particularly chilling. One evening Debbie said she got a call from a casual friend, Bianca, who asked to stop by Debbie's house. Wearing a pair of Sponge Bob pajamas, Debbie went outside to meet Bianca, who drove up in a Cadillac with two older men, Mark and Matthew. After a few minutes of visiting, Bianca said they were going to leave.
"So I went and I started to go give her a hug," Debbie told "Primetime." "And that's when she pushed me in the car."
As they sped away from her house, Debbie said that one of the men told Bianca to tie her up and said he threatened to shoot Bianca if she didn't comply.
"She tied up my hands first, and then she put the tape over my mouth. And she put tape over my eyes," Debbie said. "While she was putting tape on me, Matthew told me if I screamed or acted stupid, he'd shoot me. So I just stayed quiet."
Unbelievably, police say Debbie was kidnapped from her own driveway with her mother, Kersti, right inside. Back home with her other kids, Kersti had no idea Debbie wasn't there.
"I was in the house. I mean, it was a confusing night. I had all the kids coming in and out. The last I knew she had come back in," Kersti said. "It was just so weird that night. I mean, I normally check on all my kids, and that night I didn't. I should have."
https://www.endslaverytn.org/stories/
Violent pimps will often include a measure of loving behavior in between beatings and threats. These intermittent niceties are part of the torture process and the psychology of control.
Fifteen-year-old Lana was abducted by such brutal traffickers and traded for months between pimps across several state lines. When she was first rescued, shed been beaten so badly that a neurologist had to assess her condition.
Since her rescue, Lana and her father are living in a new town where the traffickers cannot find her. End Slavery Tennessee supplied furniture, utilities, food and rent to support the family until her fathers first paycheck arrived. The organization has also provided tutoring, school supplies, clothing and older female mentors for Lana. This family has begun what will be a very long road to emotional healing.
http://abolishchildtrafficking.org/survivors-stories/
Some traffickers just outright KIDNAP their victims, bringing them across international or state lines against their will.