Okay, I'll admit this technique works for stealing MICR check numbers and other interesting data.
Instead of using credit card generators, or subscribing to illegal networks to obtain stolen data, here's a much simpler technique. All you need to do is search the Web for an image of a credit card or a bank check, that has the numbers obscured by blur (not hard at all).
How does it work? It's rather simple "password cracking". A series of images with the numbers are compared against the image with the blurred code or number sequence, and the most probable matches are harvested. Think of it as breaking very easy CAPTCHAs.
The moral of the story: if you're going to post something online, and there's sensitive information you want to protect, you better paint black over it instead of blurring the numbers.