Not many people know, but just like steam, gog also allows devs to sell keys on other stores for us to redeem. Please consider selling them on your own website or on any other website

Well yes they are selling them, on request... or even handing it out themself. Officially, though, it is on the brink of becoming illegal and at the same time fully supported and fully valid... it is kinda a hilarious situation.

Related to fraud, i only can say... this is not a "game key issue" but a issue of a insecure payment system which is apparently vulnerable to fraud. So instead of blaming things more prone to fraud, because of their "open and exploitable nature", they should simply increase the security of the payment system ITSELF and for the fraud still happening, issuing a insurance instead of simply make everyone, including GoG, responsible, just never the payment-system.

However, it surely will take them a eternity even to accept this harsh fact that the true issue goes much deeper than just "pointing at a black sheep".