G2A still has a problem with sketchy game key resales, to the point where developers like Mike Rose have suggested that it would be better to pirate games instead. The site thinks it has a way to mitigate the problem, though. It's proposing a tool that would let verified developers block certain game keys from sale. They'd just have to paste the keys into a control panel to remove them from sale. In theory, this would prevent unscrupulous resellers from peddling keys they've obtained through bogus review requests and giveaways rigged using bots.
The company wasn't planning to do this without cooperation, though. It said that creating the tool would be "time-consuming and expensive," and asked for 100 developers to register their interest in the tool by August 15th.
This would prevent some scam-based attempts to profit off key sales. With that said, it's unlikely to satisfy some of the underlying complaints from game studios. Although G2A has promised to crack down on resales using stolen payment cards and chargebacks, this tool wouldn't stop it. The company also remains hesitant to let developers block entire games from resale, having claimed that "both sides have valid points" in that debate. There's still a distinct possibility that you'll see ill-gotten game keys on the service, then, even if they aren't as prevalent as they have been.