https://nostr.guide/nostr-protocol-for-a-censorship-free-social-network/

"On Nostr, a user can be blocked from publishing on a specific relay, but they can still publish on other relays and maintain their identity and follower base. To make it easier for users to find new relays, the client software can automatically add recommendations for new relays to the list of relays it queries whenever someone you are following posts a recommendation.

If a user wants to migrate to a new relay, they can publish a recommendation to their previous relay and move their data. If a user is banned from many relays and cannot broadcast their own recommendations, they can still let their close friends know which relay they are publishing on through other means, and these friends can publish recommendations to the new relay. This process can help the banned user’s old follower base find their posts again through the new relay. The same process applies if a relay ceases operations."

I don't know how this works practically though. How can I post a relay recommendation? Do clients implement this feature? Anyway the fedi will stress-test the censorship resistance of the network for good and we are going to find out soon :p