Non-US perspective: In my country, by law, you need to show a certificate to sit inside restaurants and bars. The government built a system that generates a QR

Non-US perspective: In my country, by law, you need to show a certificate to sit inside restaurants and bars. The government built a system that generates a QR code for patrons which can be scanned by merchants - with a government app - to verify it. The QR code has the data encrypted so no personal data is shared with the restaurant. I'm not sure if it sends anything back to the government (I guess not because of GDPR). It's worth mentioning the certificate isn't just for vaccination. You can also get it after recovering from Covid (valid for 6 months after positive test) or had a recent negative test (valid for 3 days). Going the vaccination route is the simplest option though, so in a way it is forcing people to get vaccinated if they want to resume normal life.