It does not matter whether they are aware of the updated policy, as they are from another country and are entering the states illegally. It is well known that such migration is illegal, and that there is a chance they may be caught, or die from thirst/hunger/etc while trying.

Children are separated from their parents because the parents are charged as criminals, and the children are put into government programs and foster care because they are not criminals.

It is the law.

What should be done, do you think? Allow them to go back to their country because they have young children? That's not very fair to those who attempt to migrate illegally who do not have young kids with them.

It is a shame. But the risk is well-known by the parents.