Not every missing subject wants to be found.

That’s going to be a real “duh” to my police friends, who are used to hunting for criminals. But not every missing person wants to be found, either.
Sometimes it’s embarrassment at being lost. Sometimes they’re drunk. Sometimes a mental health challenge leaves them thinking it’s a big game of hide-and-seek. In rare cases, people think they’ll be charged for SAR services (not true!)
The K9 response is to go stealth mode. The dog’s bear bell comes off their vest, the two-way radio gets turned down, and there’s no chatting with other searchers. In the words of that great outdoorsman Elmer Fudd “you go vewy vewy quietly.”
That’s harder than it sounds in most western Washington underbrush. You can limit the crunching of the brush by stepping carefully, but it slows you down. For those of us who are cussers, stifling the naughty words is hard when you find a big ol’ blackberry branch popping up between your legs. It’s a bullet we take for the team.
All kidding aside, my friend Kathy had a successful find earlier this year on a subject with Asperger’s Syndrome who was actively trying to elude her. She’s a class act, and prior experience with Asperger’s made her able to work with the subject once her dog arranged the introduction.