Google would only require 2 things. If a site has a paywallz and if the user whitelisted it. I have black listed most paywall sites manually on my Google feed.

Google would only require 2 things. If a site has a paywallz and if the user whitelisted it. I have black listed most paywall sites manually on my Google feed. So they are obviously capable and already doing the latter. And the blacklisting is easy. A click of the button and it's off my list