I've seen Battlefield 3 and other games that can't be redeemed on Steam, so I guess the rules aren't that strict in every case.
I wanted to report the BF3 one so bad (mainly coz I was jealous I couldn't enter since I'm not EU), but apparently it was a DICE dev that ran that contest. Not sure about the other games you might've seen.
Yeah, she is a gfx artist. I droped only a comment in the BF3 thread because she wanted to randomly gift 2 copies to commenters. Guess whom she picked? Me, but as I wasn't online at the given time, so she gave it to someone else instead. I'm really cursed at SG so far. ;)
But we discovered that we have some interests in common, especially World of Tanks. So it wasn't a total loss, hehe.