When one person is accusing another of scamming, it's a good idea to build a ten foot wall between them. Opening private threads where they can confront each other openly would be an invitation for drama. As evidence for this, just watch one of the scam accusation threads posted in a public forum. Even ignoring everyone else, the actual proof is buried in back-and-forth flaming and spam.
In almost all cases where a report is submitted with proof, the user accused is a scammer. Misunderstandings can be sorted out via PM or MSN, and if that fails, the dispute forum exists in case there's another side of the story that wasn't represented in the original report.