Beware of this gift card scam!

From The Consumerist:

'1)You walk in with a gift card, full of smiles and joy.
2) The Best Buy person scans your card, tell you there is nothing on it, and asks if you'd like to throw it away. You say, "Sure! Too bad! Mom said that had $100 on there, but she's off her meds!"
3) Best Buy guy steals your gift card and uses it to buy World of Warcraft Expansion Packs.

Sure, we think no one would be stupid enough to fall for this, but a Best Buy guy recently tried it on Alex, who recognized and stopped it, and he wanted to warn all of you.
From Alex's email':

charles ran the cards each time on his computer and every time it would ask him for the pin number he would just hit continue with out entering anything and say to me that the card was damaged and could not be used and if i wanted to throw it away.

I told charles that i used to work for best buy and that i knew what he was doing and that all that he had to do was just scan the card and then type the svc number in and it would work fine.