Well, I ran away from home once, when I was ten, but I was only gone for a few hours and came back home by midnight, before my mom got to the point of calling the cops on me.
I realized that, however angry and unhappy I was at home, at least it was a warm bed and a roof over my head!
As for others...
Well, a friend of my mum's once visited us and stayed a few days, and I heard from her son (later confirmed by my mom) that the two of them were on the run from his dad. So you could definitely describe them as having "gone missing".
Apparently his dad had custody and wanted him to go to school, but his mum was offering him the opportunity to take his dirt bike and go around Canada and the US racing it at festivals. Being a young teen at the time, I thought he had the coolest mom in the world and I wished I could drop out of school, run away and ride dirt bikes all the time, too. In retrospect, she was a wanted criminal, he was a kidnap victim, and the whole situation was quite horrible.
My mom told me that the judge was biased, the dad was abusive, and that they'd had to run in order to stay safe. And also that I wasn't to mention it to anyone. I don't know if that story's true, or if it's just what my mom's friend told her to justify what she was doing.
I never saw them again. That boy would be in his forties now. I hope he's had a good life!