NIP 29 is deceptively hard. Trying to implement zaps on access-controlled groups right now, and I either have to have the zapper send them to publicly writable relays, or white-list zap responses on the group relay somehow, since the zapper doesn't have permission to write to the group.
Discussion
Can the relay enforce the white-list by default but ignore it only for zap receipts?
The "Notes" part was easy.
No one was prepared for "Other stuff" part.