People try to abuse legal clauses like these all the time....they often claim innocence by accidental means, insanity, etc. This is nothing new and why we have a court cases to review the evidence of those claims.
The bigger issue here is the thirst for justice. Locking up an innocent person just because someone has to take the fall, and it might make the family feel good isnt a win for anyone. It just ruins two lives and two families instead of one. No matter how much prison time they do its never going to bring that person back, and it will never heal the families hearts. The only way to release some of that hurt is by finding forgiveness. By no means is that easy, but that is the path to peace.