Burton has had a number of frustrating conversations with health care providers and social service workers who won’t say boo about someone who friends and family are searching for.

"You can walk into a homeless shelter or a soup kitchen and they will not tell you if they're there. My mom could be in the same building as me and I would never even know it. It's heartbreaking, whenever you have a family member that is missing and living homeless, the lack of help that you get because of it," Burton said.

There’s a very big reason why most social workers and health care providers would not tell Robin if her mom was in a particular building. It’s against federal law, specifically, the Health Insurance Portability and Accountability Act of 1996. HIPAA, as most people call it, has a provision that protects the privacy of individuals' medical records, including the fact of a person’s presence in a facility.

Hartman of the Downtown Women’s Center explained staff are happy to take a message and pass it on. But it’s the homeless person’s choice whether to connect. Always. In part, because they can’t presume the best about people who say they’re searching for a loved one.

"We have women who have been trafficked or abused or exploited by family members," Hartman said. "Many of them don’t list an emergency contact. We have women who pass and we don’t know how to find a next of kin."

In other words, many of these women have good reasons they don’t want to be found. Burton gets that. She’s also seen enough to know some people are just too far gone into the abyss of mental illness, or addiction, or both.

"I had a lady that was looking for her son that was schizophrenic, and he was found after, after five or six years, and she didn't recognize him at first. You know, because the streets weather you. You change drastically. He didn't recognize her either, and he said, ‘You're not my mom.’ He's missing again," Burton said.

So far, we’ve been presuming that the right homeless person has been correctly identified. Sometimes, people eager to help say they’ve seen someone they actually haven’t.

It happened to Burton, just weeks after she returned home from skid row that first time. A volunteer from the Downtown Women's Center called Burton to say Cloudia was there.

Burton bought a plane ticket. She was sitting on that plane ahead of takeoff, when she got another call saying the volunteer was mistaken. The timing was such that Burton flew to L.A. and back: an expensive, useless and emotionally painful trip.

Now, that wouldn’t stop Burton from recommending families make every effort to file missing person reports, and take all the other recommended steps. Because the wins, when they happen, are so satisfying.

A Win in San Francisco

Corey Abernathy, and his parents, Cathy and Robert Abernathy, agreed to meet me on a bright, breezy day at one of his favorite haunts in San Francisco: Crissy Field. When he was homeless, Corey used to camp in the Presidio, not far from where tourists whiz by on their rented bicycles and children eat ice cream while wearing fleece jackets.

"I just thought too much about life. I felt a lot of pressure," Corey said. He's 5-foot-9. About 160 pounds. Hair and beard close-cropped. His blue eyes twinkle in the sun. He looks like he’s gotten a lot of sun in recent years, but nothing that seems out of the ordinary for an athletic white man in his early 30s.

Corey was 28 when he decided to throw on a backpack one day and leave his parents’ home in Willits in Mendocino County. With no warning, or explanation — though there were signs when the family looks back on it — that he wasn’t happy. That he was drifting.

"I just remember that there was like a weird amount of anxiety on me," Abernathy said. "I always tried to make sense of everything. I put too much pressure on myself that wasn’t really there. Yeah, the way I dealt with it was just drinking a lot."

He’d struggled with anxiety since childhood. He didn’t seem to have a strong idea for a career the way his older brother had. He dropped out of Sacramento State almost as soon as he got there. He lost a job in retail, then switched to a local casino. But there, he was surrounded by alcohol, and the consequences were predictable.

Corey started reading about people who dropped out of society for a different kind of life. "So it wasn’t like one single moment. It was something I was thinking about for probably like a year," he explained.

Then Corey got a DUI, something he was really ashamed about. He thought to himself, if he had no money, he wouldn’t be able to buy alcohol. And if he had nothing to worry about, he wouldn’t want to buy alcohol.

He explained, "My car got towed and I just said, ‘I’m done.’ At the time, it was a good feeling. I don’t have to deal with problems I can’t figure out anymore."

But remember, he was living with his parents at the time. And when he walked out that front door, he left no note. No explanation. His mom, Cathy, is a registered nurse. His dad, Robert, is a retired custom cabinetmaker.

His father recalled the day, "Got home and the house was empty. To me, it looked like he’d just walked out the door to go out for a walk. Everything was still in his room. Nothing disturbed. He just disappeared."

They called the police and filed a missing person’s report. Only to discover the police in Mendocino County have a loose attitude about adults who disappear, given the local marijuana growing industry’s reliance on seasonal workers. In this business, pruning is called “trimming,” and many of the trimmers come and go.

"In Mendocino County, Sonoma County if a adult is missing, they’re out trimming," Cathy said. "It was October and it was trimming season. They took the report, but they weren’t doing anything with it."

So Robert and Cathy had to start looking on their own. Corey’s friends helped. A former workmate tacking up a poster in Ukiah met a homeless person who directed them to Fort Bragg, where Robert and Cathy found Corey in a park, about six weeks after he disappeared. But Corey wouldn’t come back.

"I wasn’t ready to see them," he said.