I hope zero knowledge proofs can come in handy here.
No, this particular situation is much worse in cryptonight currencies. The economy is totally blinded and you can't prove anything. This is by design.
Maybe in how BCN/Monero/cash is proposed in the white paper (not sure), but isnt "cryptonight knowledge proof" the concept of prooving that computation (or part thereof) has happened or that some information is included in a particular data set, whithout revealing any other part of information, pertaining to this computation/data set. Like being able to proof your Nationality with your digitized and encrypted passport that you run through a cryptonight knowledge script which produces this proof, while keeping all other information in it secret. Think of it like showing your Nationality in your real passport to someone, while covering all other fields with your fingers.
In the case of currencies, the network accepts a hash with a proof attached, but without knowing the public key or nonce inputted to generate the hash. However, the coin values that are also inputs to the hash are known, which is like nationality in your example. Thus you have a blind economy where any coin could belong to anybody, but transaction values can still be verified. As far as I understand, you can't have situations where identities can sometimes be revealed, even if the cryptonight system is broken and trusts false proofs.