I remember in the UK when they first released the "stratch-it" lottery cards, shop workers were taking all the big wins. By scanning the barcode on the reverse of each of the cards, a win was indicated. This was supposed to be a safety check to confirm cards were real and to verify wins. They did catch on and made the barcode only available by scratching off a panel, thus making the card void.

Totally agree, that was one thing that bugged me.