I consider myself an honest guy and would not knowingly buy a bike that I knew was stolen. Apart from the legal aspect that, even after I've bought it, it still belongs to someone else, being a cyclist myself I know just how much we come to love our bikes and also just how much of our hard-earned gets spent on them.
I'm also in the position where I had my garage broken into and my pride-and-joy Trek road bike pinched last week. In the grand scheme of things I know it was just a piece of metal, but it was my piece of metal and I've been on some brilliant rides on it. Its particularly galling because, having a triple chain ring, it is quite uncommon, would be instantly recognisable to someone in the know. And the Police, bless 'em, they're being as helpful as possible but you can tell they just don't have a clue.
I'm quite new to this site but like what I see so far. So I have a suggestion that you create a Forum where people can list their stolen bikes. Even if its just a resource people can check before they bid on that brilliant deal they've just seen on eBay.
I'd be the first poster.