This is true for guards, middle relays, and of course exits, but less so for bridges, since their IPs are not published globally like other relays are. The people maintaining block lists can't block what they don't know.
22 karma · joined April 30, 2019
In my mind, the dream is to have the user embed an asset from our servers on their web page (like an updated version of these old CC license buttons [0]), read the referrer headers from the server logs, and then dispatch crawlers that read ccREL [1] data embedded on the page, which would allow us to instantly index content as soon as it is published. Performing broad web crawls searching the web for ccREL data is also possible but probably not what we're looking to do in the near-term.
We have a ways to go before we are able to do this, since there's no easy way for end users to create and embed ccREL at the moment, and there are of course lots of other unanswered questions about how we would moderate incorrect attribution, how these tools might be abused, etc.