Too many words, but some interesting stuff on the crack-ability of scratch cards and the implications for money laundering.

http://www.wired.com/magazine/2011/01/ff_lottery/all/1

The problem is that you aren't allowed to choose your lottery card- you get the next one off the roll.

So, using this method you could gauge your chances for winning, but only after the purchase is complete.

I don't see much advantage in it, but perhaps there's an angle I'm missing.

One story going around years ago was that somebody else was able to work out what the serial numbers meant on some other lottery cards. They got help from a shop owner who sold the cards and therefore could pick the ones that were a winning combo. No idea if its true or not.

Your debugging code can be a security hole: Contest tickets

Yes befriending a bored worker at a quickie mart to find the right lottery tickets for you doesn't seem to hard. I'm sure it's really against the law though..

The article mentions that retailers are generally willing to sell you a bulk lot of tickets as prizes for a contest/whatever and the some of them are also willing to refund you for any unscratched tickets left over.

There would be plenty of legitimate ways to get around it if you were determined. I obviously don't know the gambling laws for the US but from what I've heard about, some of them are pretty draconian and strange so maybe it is illegal to have a system at all.

The method the guy used is a simple one and does make sense as why it provides an indication of whether it is a winning ticket or not. The designers of the games didn't design it correctly to prevent this kind of information disclosure.