F22-NS: Yes
Rationale
Independent authors can sign regular events containing the same agreed single-letter tag/value. A REQ tag filter without an authors restriction returns matching events; signature verification and deduplication by author pubkey yield independent candidate identities. No shared private key or exclusive owner of that tag is required. The existing multi-relay profile permits the same reference across relays; moderation controls each relay, not global ownership of the reference. This is author discovery using selected NIP-01 primitives, not IP-style addressing, a live session, exhaustive enumeration or proof of availability. The criterion permits self-declaration and does not require simultaneous delivery.
Assessment method
Constructive NIP-01 specification analysis; no execution
Source context
NIP-01 events, signatures, single-letter tag indexes and REQ filters
Outstanding qualification
Publish events signed by two independent keys with the same agreed tag at the two selected relays. Query by tag, validate signatures, deduplicate authors and test missing/stale events and moderation. Verify no extra NIP or shared identity key is required. No live-relay experiment performed.