Why do you call them "fake giveaways"?
1. The fact that the giveaways are for DLC codes, and not full games.
2. The fact that the DLC being given away costs $99.99 on Steam.
If you don't already know, the only way to successfully redeem a DLC code on Steam is to already own the "parent" or "main" game that the DLC is for on Steam.
In this case, that parent/main game is called CrazyCar, an arguably very crappy racing game that costs $199.99 on Steam. (very overpriced shovel-ware) So, in order to even see that the DLC code is valid would require ownership of that $199.99 game.
The thing that worries me here is that I suspect that a cheaper DLC code for some other obscure game is the code that was actually given away. This would pull up the failure to redeem message associated with not owning the parent/main game upon an attempt to redeeem the code. This could in turn trick the winner into providing a positive feedback thinking that the code is for the DLC labeled.
These giveaways just scream fraud, as they are in my honest opinion a rehash of the fake giveaways for the game "Ascent Free-Roaming VR Exerience" or the DLC "Clickteam Fusion 2.5 Developer Upgrade" that I've previously reported to IndieGala staff. The nefarious person just searches Steam for an overpriced item, then starts giveaways for it claiming to be giving that item away without even having any valid keys.