Anyone without a badge can be assumed to be unvacinated.
Let's use AIDS for example, they make a badge that is certified AIDS free and then offer free AIDS testing then you can assume anyone without the badge has AIDS.
This is a hipaa violation by publishing some users information that has approval and waivers you are exposing the other users information.
Going with this example, let's say you have a group of people who voted wrong and you want to punish them, you don't let them display the AIDS free badge. It is an abuse vector.
HIPAA only applies to "covered entities" (e.g. healthcare providers). It's why your employer is allowed to ask about your COVID vaccination status (even if they are also a healthcare provider).