In truth, John,
it's important to air this stuff publicly. We've got trading reputations on the line here.
If anyone ripped me off on an item offered in the "Offering/Looking for" section, I would blast them publicly on the forum as well. Similarly, if someone were to accuse me of ripping them off, I would wish to defend myself publicly as well.
It's the correct thing to do. We use an "honors" system here...