Ron, I think that most of the victims of fraud are trying to grab the items in impossibly good conditions for impossibly low prices. If you know the reasonable balance between the rarity, the condition and the price, it is easy to know that such things they hunt for are virtually non-existent.
The only rare items I have hunt for on Amazon or ebay are CDs, and I have no bad experiences. I've never bid and only bought "buy it now" items and stayed away from Yahoo auction, though.