Like the idea, tho. Just wondering. Although, I guess you could just not-serve it to anyone other than the originator.
Discussion
that was already done a long time back, i have a test in the kinds library that categorises sensitive data and it is used to filter subscriptions and requests from matching on it without being a relevant party with auth enabled
DMs, giftwraps, and application specific data...
https://github.com/mleku/realy/blob/dev/kind/kind.go#L45
these are events that should, with auth enabled, never be sent out to any npub without their npub appearing in the event (either author or tagged)