I don't agree with imposing that consequence. Their parents are a priori scum. That's enough to deal with. If they have kept their nose clean and been productive despite that, those are people we want here. Producers.
it also comes down to personal responsibility. Punishing them for what their parents did without their knowledge or consent is collective punishment. If - and only if - they have proven themselves as indiviuals, then they should be rewarded with being allowed to keep their lives here.
Individuals PIMF
Bank robbers, rapists, murderers and other lawbreakers, who happen to be parents, usually also commit their crimes without their children's knowledge or consent. Yet they are still separated from their children.
Besides, what's so cruel and horrible about making an illegal alien's children go back to the old country with him? As another Freeper once pointed out, when a member of the U.S. military is transferred from one location to another, his or her children have to move, also. This is often traumatic, as the children are torn from their school and their friends. The children didn't ask for their parent to go into the military. Yet nobody feels sorry for them.