Our products are legit bought games from different regions they are completely legal. And yes Steam can Ban or Delete your game with any reason but the chances are very small about %0.01 but if u experience this please contact support chat.

People buy games in regions where they're cheaper and then resell the keys for a profit to people from different regions where the game costs more. It's quite common and they can do this because the keys themselves are not region restricted. Sometimes keys from these sellers are of questionable origin. It's understandable to be cautious because there is always a slight risk. There's no guarantee that the keys being sold were not stolen.

These sorts of game keys are generally not risky when they're sourced from actual retail copies (y'know, the ones that come with a disc and possibly a manual/leaflet), but seeing as how CS:GO hasn't had a retail release... the ones these guys are selling must be from proxy/VPN purchases. Right?

Well your comment made me think too and so I'd say that this site is quite safe and legit because it's using OpenID :
http://steamcommunity.com/dev
Well I know it's not 100% guaranteed that it's a true key but I'm hoping you can find some solution with the staff if something happens.