Thanks Hendrik!
Yeah, that's understandable. And maybe, I phrased it a bit too complicated. Let me put it this way:
It would be cool, if there were an additional level of DLNA library access, between fully privileged and unprivileged (read-only). This could be called e.g. HTPC access and would only allow the client to update the two(?) fields required to keep track of what has been watched.
What about that? There'd be no user configuration for this.
I can't imagine everybody with a library server has/wants the client running with fully privileged library access? If I think about my other HTPC "users", there's a high probability for them to just accidentally delete stuff or change it... Because you can't kill Disney+ or Amazon Prime with your remote, can you? So I consider it a legitimate thought for a user to assume he/she can't cause any harm from the client side (if the user even knows about the server/client model at all).
Having this type of library access would put a JRiver powered HTPC closer to the experience a fully commercial device. In that light (user experience), I would even say it could be considered "essential" functionality. It might not be easy (I don't know anything about the application structure/architecture), but maybe it is something to think about, for future overhauls etc.