Ask HN: Covid-pass apps matching data with 3rd party databases?

What's to stop Covid passport scanning apps from matching the scanned certificate with a third party databaes?

The EU green pass is asked asked at numerous locations and contains personally identifiable information in the QR code that is scanned. What measures are in place to prevent the scanning app from displaying asociated information from other public databases such as bad debotros, sex offenders, or https://dbs.anumuseum.org.il ?