iippo: God knows where the smaller sellers get their key from on Kinguin, but supposedly G2Play keys are legit.
I'm pretty sure G2 did sell some russian keys that caused issues for many issues because of region locks a few years ago. I wouldn't call reselling russian keys that require a VPN to register "legit".
iippo: I think they get their keys from the game boxes of cheaper countries and aim to sell on western markets cheaper.
Nope. THe thing is that we don't have any idea of how they get those keys so cheap. Even boxed games are not that cheap. Besides, how many times have we seen these sites selling games on PRE-ORDER for a fraction of the normal price? If they got their keys from retail boxes, they wouldn't sell games on pre-order.
Remember the Natural Selection 2 keys that were bought with false credit cards and then were revoked by Steam? Remember the stolen keys for Sniper Elite 3 that were also revoked from Steam? THis is the kind of thing that happens with those shady resellers. They don't care about where the leys come from, they just get them as cheap as possible to resell them. And the consumers are the ones taking the risk of getting a stolen key that will later be revoked.