Dumping keys like this is not an ideal way to share your good fortune. If the keys don't get snatched up by spambots, they could get swiped by key resellers. On your end, you would never know; there is no way to see the journey your code makes from this forum post to someone else's account.
It is much more responsible, and just as generous, to live by the adage that forum user Momo1991 coined, "MAHAYO!" This stands for Make A Human Answer You, Okay? Translation: if you want to give away a GOG code, make the interested user reply to your post saying that they want it. From there, send it to them via Chat so that the code is never seen by anyone other than the two of you.
Granted, the person you give your code to in this way could still be a dirty key seller, but at least you will have a better "breadcrumb trail" to find that out. If you gave the code to Johnny, but your Account Details show that it was redeemed by Suzie, then you can at least see that Johnny pulled something shady. Just dumping a code in a forum post almost never helps anyone worth helping.
Please, gift responsibly. MAHAYO!