Most efficient way to claim GOG games and block added disruptions:

1. Log in to GOG
2. Open this link: https://www.gog.com/giveaway/claim (a correct auto-claim will just show {} in the top-left with nothing else; then close the tab)
3. Open this link and undo any/all resulting auto-subscriptions as you prefer: https://www.gog.com/account/settings/subscriptions