This makes sense to me. Part of me wonders if this system wouldn't work better in reverse, a blocklist instead of a banlist. Blocklists can spread via URL, in the same way that DNS or email blocklists work. Subscribe to the blocklists of people you trust.

I _think_ this removes the motivation for low-quality PRs. Get on a major blocklist and the GitHub account is basically dead. People could make new GitHub accounts, but then you never get an "impressive" GitHub account.