They have two options: leave or actively do the right thing (provide intel, sabotage infrastructure, etc). Otherwise they are low priority military targets merely because they pay taxes, participate in enemy economy, are an available mobilization resource and so on.
Discussion
Kids can't move on their own. Likely many are already doing just that and providing intel and sabotaging infrastructure, trying to undermine or overthrow the regime for years, it just a secret and not shown in media. What now?
Nothing, good for them. As for the rest who can be considered innocent, I don't care about them, just like enemy does not care about our innocents, such things should be considered before the war and is a reason normal people don't start it if they can.