In today's Scummy G2A news....
G2A have said they will develop a program that will block keys that they have been given by the developers. Basically a blacklist...
Small Caveat
They will only do this work if 100 developers sign up to it.
They can then publish the list of devs who have signed up...
So really it's a marketing ploy...
"Oooo look such and such a dev is signed up to the G2A's blocking program!!! they must be affiliated with us now!"
Oh yeah and they will only block Review Keys and giveaway Keys... Not purchased keys (stolen one's which is the real issue)
Linky link link