To the trained eye the above image might be an obvious fake Patek Philippe Ref.2499 second series, but when you don't have a trained eye, it's accompanied by a genuine Patek Extract from the Archives and the guy selling it is letting it go at an attractive price because he has a gambling debt and needs the money fast, you could be tempted to try and buy cheap to make a quick profit. Sound ridiculous? It's a true story.
I took these pictures after a collector was offered a 'Patek 2499' and wanted a second opinion, the price? A cool US$650,000. The seller had bought it from someone who was in need of cash fast and so he though he got a good deal, he didn't. The numbers on the watch and certificate were copied from a genuine Ref.2499 sold at auction years prior and hence an Extract from the Archives would have been provided. A few minutes of research could have proved there were two watches with the same numbers but I guess when all you can think about is how to spend the profit, reason goes out of the window.
As far as I know he never got his money back.