Great comment. Yeah, at a technical level I think it's pretty possible to make everything invisible. Because you can encrypt everything, location sending, etc, etc, etc.

I think Nostr is a great platform for identity and reputation management, in general. So yeah, it could be great for this too.

In other words, an npub and being able to verify that this npub made a review on another npub is fundamental. It's a system of vouching for one another in essence. A voucher system can or probably really should be built with Nostr. Because what else could be better in this case?