We're discussing those who were illegally brought to the United States as children who "lacked the intent to violate the law," and pose few national security risks. In our courts we make a distinction between those who chose to violate our laws and those who had no choice.
Unfortunately that can't be taken into consideration.
It's worse than a slippery slope, it's a slippery cliff. Let any illegal immigrant stay for any reason and you will open the flood gates for it to happen en-mass. Any illegal immigrant caught inside the US should be deported. Whether or not they should be fined or jailed depends on the individual situation. If we are that worried about the children then waive the fine and jail time for the parents and send them home in a nice comfy bus.
This is my second choice of action though. My first choice would be to take away everything that draws them here (jobs, homes, welfare, ect.) and watch them leave of their own accord.