I've never bought into this solution (except in a few special circumstances) because I don't believe that people behave like this. It's the one reason I've never totally bought into Orson Scott Card's Speaker for the Dead idea. At the base of both is this profoundly naive idea that confronting people verbally with THE TRUTH will somehow break down their defenses.
And I always wonder: who ARE these people? Because the people that I know and the person that I am are much more self-protective. Sayers captured this perfectly in Gaudy Night when Harriet says, about her trial, that if she had committed the murder, she probably would have felt totally justified and felt extremely put upon that she'd been arrested at all.
Because that's how people truly behave. C.S. Lewis understood this (just read Screwtape Letters) and Jesus understood this (that's what all the "those who have ears to hear" stuff is about). But lots of people don't. There's probably even a part of me that thinks that if you could just say "it" (THE TRUTH about a crime or That Person or The Family or The President or politics, etc. etc.) in the right way, other people would go "Ooh-eer, I never thought of that before. Of course, now you've said it, you're right."
But really, people don't behave like that. If a Speaker for the Dead really did show up at a funeral, half the people would disagree and half would be offended and okay, the two people who thought he (she) was spot on would use it as some sort of weapon: "Ha, ha, you see we were right."
It isn't that I'm depressingly negative and think that people don't want to hear THE TRUTH or that I am confusedly relativistic and think there are "so many kinds of truth" la la la. It's that I think that truth is approached through the lens of personality. I've had conversations with people where I've realized that we didn't exactly disagree, we just came at the same point very differently. Like the fact that both lefties and religious righties think we live in a corrupt, hedonistic society, but they get to that place on completely different trains. And even I wouldn't disagree with EVERYTHING they say (I just don't want to end up at that place; I'd rather wave at it from the window).
It's why my Church has a point when it says that you can't convert people through argument; they have to feel the spirit. Despite the fact that I sometimes think members use "feeling the spirit" as an excuse not to use their noggins. But still, the point is valid.
Because the idea that one speech or one perspective or one approach will suddenly bring people together or force a confession is just, well, kind of silly. Even setting aside the defensiveness of human beings and the fact that people can lie to themselves and that criminals are not exactly renowned for thinking clearly, it's kind of silly. It's up there with people who think international problems could all be solved if the right people would just sit down and talk--it's a fundamentally academic idea: eloquent language is so powerful it will shatter people's innate convictions, their personal beliefs, their views of the universe and their very big guns just like that.
Back to murders: there are some exceptions. I buy the end of Murder in Mesopotamia, for instance. But then when the murderer confesses, he doesn't break down and cry, he just says, "I'm so tired." I don't buy the end of Murder at the Bellona Club since I think the murderer was too self-protective to gracefully confess and then shoot himself. Like I've said, I rarely buy Ann Perry endings. The ending of Murder on the Orient Express is perfect (but has never been done correctly on film or radio, despite Lauren Bacall: the mama should start bellowing in a strong Southern voice). In real life, I think murderers are probably a lot like they are on CSI where they give up information when they think it will help them. Or Barney Miller where they shrug their shoulders and call their lawyers. Isn't that how most of us behave? Change is a long-term internal process, not instant pesto "I'm so happy now." (One of my disagreements with Touched By An Angel--oh, don't get me started!)