Is this safe?

I was hoping to win that one, congrats. As to its legitimacy, there's really no way to know unfortunately. The fact that it's a key, and NOT a gift thru steam puts up a red flag for me.

I didn't enter that one cause he changed it from key to 4 pack, I'd avoid it.

3 copies of AAA-game
Keys instead of Steam gift
Keys probably were exploited
First giveaway from this user

I think you shouldn't activate this key.

I knew it, he didnt have it in his inventory, you should go to steam support and ask if the key is legit or it is one of the leaked ones, you wont lose anything if you do that.

If you activate it... not much harm apparently since Steam will just remove it from your library. If that happens, I would report the maker of the giveaway!

Send Steam support a message telling them how you got it and that you are worried about it being an exploit. That way you have something on record before they catch you.

Activating it means that you won't have someone activate it before you do, which is a risk when an untrustworthy person knows the key.

The worse thing that could possibly happen to you is the removal of the game from your Library. If you ask support if the key is legit, they'll most likely deny it is if it perhaps wasn't purchased from Steam.

Even if u activate it and its a leaked key they will just remove it from ur account nothing more. I got Dead Island for 4 coals, yeah its a key, yeah its probably leaked, but its still in my libraly

just give it to me :)

People have been going around on the Steam forums offering up Dead Island for just about anything you can imagine. I was offered Dead Island for my L4D2. Now, I knew of the leaked keys from way before and figured that one was (at least mostly) cleaned up. However, with the huge influx of Dead Island keys again, I had to pass. The fact that I already have Dead Island on both Steam and 360 helped me to skip over that too. I just don't trust keys from others. Won a key on here once and it was a duplicate key. Raffler said he didn't know why, and rather than make a stink, I just let it go.

TL:DR I don't trust keys from others. Passing through too many hands is a hazard.

I would personally pass all giveaways that contain CD-Keys.

What can happen if this key is "bad"? He would just lost this game from his account. Nothing bad to account itself, right?

From the FAQ
Do not submit what we consider exploited CD-keys (Serious Sam: Double D, Dead Island, Bulletstorm, Homefront Shotgun DLC, AI War, Portal 2, Dirt 3, Dark Messiah of Might & Magic Multiplayer, Eets, etc).

So, you could get support involved if you want

In all honesty, if you activate it the worst that happens is it disappears from your inventory at a later date.

Well, when I got a key, it worked, but that four pack thing sounds suspicious.

I was hoping to win that one, thought it was a gifted copy...Worst case they take the game away.