silverpill@mitra.social I thought about checking against the outbox, but there's a potential race condition that could occur if I receive the Create(Note) at roughly the same time as the community, but the community hasn't processed the activity yet. In that scenario, the activity would not be in the outbox for checking.
The same thing would happen if there was some out-of-band check for object membership in a collection (not that there is one right now).