I can find some stories on the Internet about a wealthy person doing this:

http://lego.gizmodo.com/high-profile-silicon-valley-exec-gui...

http://gizmodo.com/5912141/multimillionaire-software-exec-ar...

http://news.yahoo.com/blogs/technology-blog/incredibly-wealt...

http://www.mercurynews.com/ci_20675946/silicon-valley-tech-e...

But there's this earlier story too:

http://www.eurobricks.com/forum/index.php?showtopic=29272

Wasn't there a site years ago that hosted images of bar codes for just about any common item sold at chain stores? I seem to remember the idea being that you could just print out something with a lower price that's still believable and stick it on the item before checking out. The idea was that if anyone caught on, you would claim ignorance and apologize.

From what I remember this didn't work out well for anyone and was handled as you might expect. I'm definitely not someone who would try to give himself a $500 discount on an HDTV but it got me musing about the scam when it crossed my radar. It always seemed to me that in order to be worth the risk and hassle you'd have to do it on a scale that dramatically increased your chances of getting busted. Like you couldn't give yourself a big discount (obvious at checkout) or give yourself lots of little discounts (more chances to get noticed) so aside from the "heehee I found a dirty trick" aspect, it seemed like kind of a terrible scheme (not even counting the fact that you're engaging in fraud).

Related, this is why manufacturer's coupons have changed in the last few years. It was previously possible to create a manufacturers coupon barcode for any UPC that would represent one of the standard discounts before GS1-128 including Buy 1 get 1. The new GS1 barcodes encode much more data that allows better fraud protection.