Hickory: Yes, Steam do revoke keys when they're informed of stolen ones. This is not unique to GOG.
No, terminating your *stolen* key.
Adamandio: And how is the customer supposed to know its stolen ? Ive been told in the past by many people that g2a is reliable and have bought about 5-6 games on there, only 2 being gog's. For the Steam games bought there i gavent had problems in over a year buying them. I see that you are trying to defend Gog's position and i know that they are only trying to stop stolen keys selling and stuff but from a customer point of view this is awful and i feel both scammed and betrayed.
Look, don't get angry with the innocent here. Get angry with the company who resells stolen keys. You are misdirecting your ire at the wrong people. Whenever you buy anything from anywhere it is always a case of do your homework, *never* buy from shady market places (G2A, Kinguin etc.) and 'buyer beware'. GOG have done no wrong. G2A *have*.