Not to be controversial but I’ve traveled to a lot of countries and I’ve had to provide proof of vaccination for various diseases to many of them (yellow fever, etc). I went to elementary, middle, high school, and college and had to prove at each stage that I had been vaccinated. I volunteered at a hospital for many years, and had to prove I’d been vaccinated. Throughout history individuals and whole areas have been quarantined and travel restricted, both in the US and elsewhere, to prevent the spread of disease. Proofs of vaccination or immunity required for travel have existed for literally hundreds of years.
This isn’t a new concept. It’s interesting that it only became “a threat to freedom” when certain people decided to demonize basic public health for electoral power.
You’re absolutely right. Not everything needs to have a technical component; and putting a serial number on a piece of paper that correlates with a database takes you a hell of a long way to preventing fraud. Combined with serology to check for antibodies (regardless of fraud) and there’s no need for tech to get into this beyond the usual use of databases.
The most challenging part will be getting states to issue proper exemption ids to those who need them, and not putting the exemption on regular id.