I have a copy of the full leaked list (it is close to 3mil) and I also have some valid coupons from gpu purchases and let me tell you that list contains EVERY code from AMD's promotion of graphics cards and other related offers.
Steam support have said via twitter that they will not be banning accounts though you may wish to keep photographic evidence of any coupon codes for future use to prove legitimacy.
Also, I have just found this piece of information:
Update: The 3 million steam keys for Dirt 3 that I posted here have been invalidated by valve after the whole thing broke up into the international gaming press.
All of you that managed to register keys to your accounts are probably going to get to keep the game and if not, then the worst case scenario is that your game will disappear from your steam list.
Valve has assured that steam accounts will not get banned over this so rest assured!
For all of you that are too late, I am sad to inform you that you are... well... TOO LATE...
I hope many of you and your friends got to register as many keys as you could fit in your pockets.
I am not going to lock this topic for the time being so feel free to talk about your experience with the keys and if any of you loses the game from your account, post about it here.
The fun is officially over!
So it looks like all of the promotional keys are now null and void from this point forward. AMD are claiming to still honour these keys at some point, not sure when/how.