that's terrible. i don't remember what i've posted in this thread so i'll risk repeating myself: i'm against any policy created to antagonize people who want a better life.
i think it's reasonable(not close to the main concern tho) to ask why the parent hasn't found a way back to the child. the answer is almost certainly because either the database that tracks where non-citizens are detained is shitty or the parent is afraid of law enforcement.
i've represented a few illegal immigrants in criminal matters. in a huge majority of these cases the victim was another illegal. in some the crime was a battery in a hotel between two co-workers on a construction crew. but a lot of these incidents resulted from one dude ripping another off in some manner, either not repaying a loan or destroying property. if you're a non-citizen and get cheated there is no legal recourse, so you smash up his car or kick his ass. the fear of law enforcement and the plain lack of access to courts actually makes it pretty damn hard to live according to the law. i don't know what the solution is. maybe if you successfully sue someone you get a citizenship pass with your settlement check?