Can't relays sniff something from the combination of auth, welcome event, group ID, and IP address?
Discussion
If a relay requires auth, then yes — it could sniff some information. As for the other points:
– The welcome event is wrapped in a NIP-17 DM, so it’s not linked to the MLS group.
– Group IDs can be rotated, even per message.
– IPs can be hidden by using the Tor network.
Also, some information can be obtained from the req, but auth is required to identify the sender.
Thanks for elaborating. Ultimately, it means each group should use its own relay.