] [Think like a T-shirt that when worn would make
] you difficult to photograph, or artists discreetly embedding
] such watermarks inside photos that they dont want
] photoshopp'ed, etc.]
] Consider this a call for any comments/knowledge relating to
] this issue.
I don't know if this qualifies, but I thought if it as I was reading. It is a clear spray that you can put over your license plate that prevents cameras from being able to capture it on film. I found it interesting.
RE: Photoshop Currency Detection