Allison is a hypocrite. She wanted the female suspect in "Truth Be Told" so badly to admit she killed the two home invaders, one of which raped her. She demanded she tell the DA she killed the two guys and looked self-righteous doing it. Yet she had no problem letting Blythe Danner's character walk away without consequences for the pre-meditated murder of her own daughter in "A Taste of Her Own Medicine". She even knew where the daughter's body was buried and let them pore the pool overtop of it. Where was Allison in that episode when the truth needed to be told to the DA? It sets a bad precedent for the show, if Allison is willing to let some murderers skate because they killed for what she feels is good reason. Makes you wonder....I'm guessing killing the guy who just raped you and his accomplice still suffering shock from the attack isn't an ignorable murder by Allison's standards but killing an evil daughter who poisons children all the while pretending she went missing because you don't want you're son-in-law and granddaughter to know what kind of monster she really was makes Allison's do not prosecute list.
In past episodes she has told victims that have commited "justifiable" murder that justice is blind and she has to tell the truth about what happened no matter what the circumstance. For example, In one past episode she uncovered a woman fugitive who had killed a policeman accidently when she fought back when he tried to rape her during a traffic stop. In that episode she gave her a head start out of town before she told the DA what she knew. The key being that she was compelled to tell the DA what she knew even if she felt for the woman. If Allison is going to be a self-righteous nag all the time and demand the truth from people, then she cannot pick and choose what to report on a crime. To do so makes her character lose all credibility with the audience.