Dragonmarks in the wrong houses

[moonfly7]

So, I've been reading through Eberron Rising in preparation for an Eberron game I'm going to run and I came across something intriguing, among the dragon mark backgrounds is something called the foundling. Basically someone with a dragonmark who isn't connected to a house, but isn't Aberrant.
So this got me thinking: what if someone in a house, let's say a more open minded one like Tharashk or Deneith, or maybe Medani and Lyrandar since they're both half-elves and half-elves stick together in Eberron, we're to adopt a child to give them a better life. Maybe it's the kid of a friend that died in the war.
Regardless, they raise the child, and they grow up in their adopted parents house, let's say house Medani because of half elf unity. When they reach adolescence the adopted teen suddenly manifests the mark of the Storm, something that was obviously not directly in their blood but must have lain dormant in their line, but has now shown itself.
Here's my question: what would the houses do in a situation like this? The kids been raised as member of house Medani(though a lower ranking member as its not by blood) but now manifests powers that could threaten house Lyrandars monopoly. Obviously I doubt Medani or any house that suddenly found themselves in possession of a new power opportunity would be that upset, but imagine what the house of that dragonmark must be thinking knowing a rival house has access to their powers.
So I guess I'm asking you more experienced players, what's likely to happen? Nothing? Or something very, very bad?

[JackPhoenix]

Problem with adopting people with different dragonmarks is that mixing marks is one sure-fire way to get aberrants. That alone would be a big incentive to send them away, to avoid any problems further along the line. And the adopting house wouldn't exactly have access to rival house's powers: Yes, the dragonmarked individual has few magical abilities, but the house that adopted him lacks the knowledge to develop those abilities, and the tools the other houses developed over centuries or millenia that work with those abilities. It's those tools... dragonshard foci.... that make dragonmarks useful and valuable, the benefits of the mark itself are fairy minor and generally replicable by standard magic. Needless to say, dragonshard foci are trade secrets of their respective houses.

There's also the Twelve: I'd expect the house to which the dragonmark belongs to demand the individual's transfer to his proper "family", if something like that isn't already part of their rules.

[moonfly7]

Problem with adopting people with different dragonmarks is that mixing marks is one sure-fire way to get aberrants. That alone would be a big incentive to send them away, to avoid any problems further along the line. And the adopting house wouldn't exactly have access to rival house's powers: Yes, the dragonmarked individual has few magical abilities, but the house that adopted him lacks the knowledge to develop those abilities, and the tools the other houses developed over centuries or millenia that work with those abilities. It's those tools... dragonshard foci.... that make dragonmarks useful and valuable, the benefits of the mark itself are fairy minor and generally replicable by standard magic. Needless to say, dragonshard foci are trade secrets of their respective houses.

There's also the Twelve: I'd expect the house to which the dragonmark belongs to demand the individual's transfer to his proper "family", if something like that isn't already part of their rules.

Right, which would make total since. But here's where I'm getting confused: the houses don't care that foundlings exist normally. They don't claim them as part of the family's because they aren't anymore. They no longer have a connection to the houses, so if the twelve tried to rule on a foundlings adoption like that it would create a dangerous precedent that I think would've already been made a law if the houses cared that much.
But I think your right: without the focus items your much less useful with your mark. So, assumingly, the other house might not care that much. Which would allow for an interesting NPC who was of one house, but bore another's mark.

[HappyDaze]

So, I've been reading through Eberron Rising in preparation for an Eberron game I'm going to run and I came across something intriguing, among the dragon mark backgrounds is something called the foundling. Basically someone with a dragonmark who isn't connected to a house, but isn't Aberrant.
So this got me thinking: what if someone in a house, let's say a more open minded one like Tharashk or Deneith, or maybe Medani and Lyrandar since they're both half-elves and half-elves stick together in Eberron, we're to adopt a child to give them a better life. Maybe it's the kid of a friend that died in the war.
Regardless, they raise the child, and they grow up in their adopted parents house, let's say house Medani because of half elf unity. When they reach adolescence the adopted teen suddenly manifests the mark of the Storm, something that was obviously not directly in their blood but must have lain dormant in their line, but has now shown itself.
Here's my question: what would the houses do in a situation like this? The kids been raised as member of house Medani(though a lower ranking member as its not by blood) but now manifests powers that could threaten house Lyrandars monopoly. Obviously I doubt Medani or any house that suddenly found themselves in possession of a new power opportunity would be that upset, but imagine what the house of that dragonmark must be thinking knowing a rival house has access to their powers.
So I guess I'm asking you more experienced players, what's likely to happen? Nothing? Or something very, very bad?

They would give them back to the house of their blood. They would expect the same in return. There is nothing to be gained from trying to claim something (someone) that is obviously a part of another house, and the Mark makes that ownership/belonging very obvious. No house would stand for any house trying something like this, and 11-on-1 odds are too much for any house to take on.