[pokergrader]

It is dreaming. Current OCR and image processing is so powerful the level of "smearing" necessary for a computer to mess up would make it totally unreadable for the human players.

Just look at how complex current CAPTCHAs have to be in order to fool the bots.

And while messing around with the card images and making them harder to modify would certainly be a good step to prevent casual bot makers, slightly more complex software would easily handle it.

dave's idea up there seems pretty bullet-proof, but of course nobody would play on a system like that.