Runaways "aging out"?

I believe when minors runaway from home, they are somewhat considered criminals merely for that. As in, even if they have done nothing that would be considered illegal if they were adult, they can be detained by police, and then taken home or to juvenile facilities or whatever against their will.

How about the magic moment they turn 18? Does that criminal status immediately go away and there are no ‘lingering’ effects?

As in, say a sixteen year old girl runs away with her boyfriend, and the parents report her to the police for this. She and boyfriend just go somewhere and live peacefully for a while – get jobs, rent a room off of some other person, just live without committing any other crime. Well, except for probably committing ‘guilty of perjury’ things by lying about their names on work applications and so forth.

So one day before Mary turns 18, some cop happens to recognize her and takes her to the police station, and they call her parents. (I’m assuming that’s what they do?) Anyway, parents are all happy and say they’ll come and get her…but it’s late in the day and they’re hundreds of miles away, and they can’t get there until the next day.

Do the police keep Mary overnight, then just automatically turn her loose the next morning? Because she is then an adult and has every right to choose to live wherever she wants regardless of her parents?

Or is she still ‘guilty’ because she HAD been a runaway, and so they hold her for that? Do they continue to hold her until her parents will arrive at noon the next day and turn her over to them anyway? Or do something else restricting her at that point?

Do they sort of acknowledge pragmatic reality the previous day, that nothing worthy of police intervention is going on, tell the parents not to bother, and turn her loose immediately?

They’re not regarded as criminals or quasi-criminals. Police will detain a runaway child for return to the parents, but not as an act of criminal prosecution; rather as a way of enforcing the custodial powers which parents have over their children as a part of their guardianship over the child. This custody expires when the child reaches the age of majority, so yes, as soon as the child reaches that age. This is without prejudice to the possibility to prosecute crimes that were committed previously, such as the perjury example you’re giving.

It may also be that third parties who assisted minors during the runaway phase can be prosecuted for abduction, but the children themselves are not treated as criminals for running away.

Yes. Once someone turns 18 their parents have no say in their lives except by choice. In some cases parents could claim their child is incompetent, and possibly succeed in getting a court order. Recall the Brittney Spears situation, even though she was over 18 when that started, and she seemed to be avoiding a worse situation by subjugating herself to that status. Assuming no such circumstances her parents have little chance of success since the child can hire their own attorney.

Minors aren’t considered criminals when they run away from home. Parents may be able to seek court intervention* if a child behaves in certain ways such as refusing to attend school or running away (these used to be known as “status offenses” and refers to behaviors which wouldn’t be a crime if committed by an adult) and the court might place the child in a facility but it’s not a crime with a sentence to be served and the court loses jurisdiction at the latest when the child turns 18. So the police might keep Mary at the station overnight or they can spend their time trying to find a foster/group home for her overnight - which will in reality only be a few hours as she will turn 18 when the clock strikes midnight. In other words, she’s staying at the police station if they even bother with that.

* In my state, this is done by filing a petition which contains a description of the child’s behavior and asking Family Court to declare the child a “person in need of supervision” (PINS)

This is from personal experience several decades ago, laws change and vary by state, etc. so make of this what you will. In said incident, a minor ran away and travelled through several states before being detained by the police. Simply being a runaway wasn’t a crime, and they could only detain said minor for 24 hours without having to charge them with something or release them from custody. A parent had to fly down to pick them up and take them back home.

This sounds bizarre. If the parent had not showed up, surely the police cannot just turf a minor out on the street. Wouldn’t they need to call social services?

It varies by jurisdiction. In California, running away isn’t a crime per se, but the authorities will try to either return you to your parents or contain you somewhere else so you’re not on the streets. There are two separate juvenile court systems: delinquency and dependency. Delinquency (Welfare & Institutions Code, section 600 et seq) deals with minors committing criminal acts and status offenses (running away, truancy, drug abuse), while dependency (WIC 300 et seq) historically only dealt with children who were abused or neglected. But in recent years, dependency has been edging in on those runaways etc. The long-standing split of authority over whether the dependency court could take jurisdiction over a child placing herself at risk (i.e. the parents/guardians weren’t at fault) was resolved by our state supreme court in 2017, who said, essentially, yup.

It’s possible for the two courts to have dual jurisdiction over a child, with one court taking the lead. I don’t know as much about the delinquency side of things, but I know that the children’s attorneys in dependency are always fighting for their clients to be declared dependents and for dependency court to take the lead, because that can mean a less restrictive placement for the child (foster home vs. juvenile hall or similar facility). But typically, if all a kid has done wrong is run away from home, they’re not likely to be placed somewhere they can’t also run away from, if they’re so inclined. The court will issue a protective custody warrant (similar to an arrest warrant), so that if the police find the kid, they’ll take him/her in. But they still won’t keep the kid in jail. Some kids, especially those who have been sexually trafficked, just keep going back to their pimps. In LA County there’s a designated CSEC (commercially sexually exploited children) courtroom for these cases, but I don’t know how much of a difference it’s made. I do feel like the child welfare agency bends over backwards to try to find these kids a place they’re willing to stay. I’ve seen them gun hard against parents who did nothing wrong just because the kid says they refuse to stay there; I’ve also seen them do an abrupt about-face on parents they were sure were garbage (and maybe weren’t wrong about) if the only place the kid will stay is home. Sometimes the only reason a girl will eventually accept help is because she becomes pregnant and is afraid of her baby being taken away.

Once a child turns 18, they’re out of the system unless they opt back in and meet the requirements. There’s a program called AB-12 for foster youth who aged out that helps them with funding for housing and school for the next few years. But if the former foster youth stops showing up to meetings and court dates, the police don’t drag them back; they just get dropped from the program.