You could fix 2 by having a verifier that puts the note in a Faraday cage. While...

jefftk on Dec 11, 2019 | parent | context | favorite | on: Show HN: Kong – Physical Cryptocurrency

You could fix 2 by having a verifier that puts the note in a Faraday cage. While that's more work than just scanning with your phone it could still be cheap and worth it if you were receiving a lot of notes.