[justansenoob]

There's a problem with this.

If you go to the store to get the S/N, the c@rd isn't going to be activated until someone buys it from the store, not to mention that you'd have to perform the SE before someone redeems it after it gets activated. If it worked for you when you did it then you got really lucky. You'd have a higher chance of success if you got the S/N from an image on ebay or craigslist.