What's wrong with a vaccine passport?

And no, this is not an idle question. I really would like to know what the objections are.

We don't have "identity cards" in Downunder. They were seriously considered at one time but the idea proved unpopular. I doubt they are really necessary now. The digital age has changed that. We do have "Medicare" cards and they serve much the same purpose.

Most people also have credit cards or debit cards. We have library cards, driving licences, travel passes, membership cards, loyalty cards, and more. If we want to travel overseas (when we can) we need a passport. 

I have a "proof of age" card with a photograph - the alternative to a driving licence. I need it for certain transactions.

For many years I had to use my passport to provide "photo ID" - or a form of proof that I was who I said I was. I still need it occasionally because the "proof of age" card is not accepted by certain institutions. (The wholly ridiculous thing being that, in order to get the proof of age card, I had to provide 100 points of ID and the passport provided the bulk of these!)

Proving my identity has been necessary to sign legal documents, open a bank account for charitable purposes, meet senior officials and gain entrance to a number of places. 

In order to visit the Senior Cat I need to sign in to the building. I was required to have a 'flu vaccination - which I would have had anyway. Next year we will almost certainly be required to show we have had Covid19 vaccinations as well.

I have never questioned  this. It has all been part of the security routine. It isn't just about keeping other people safe either, it is about keeping me safe too. 

So, what is the problem with showing that we have been vaccinated?  Most people will get vaccinated. It will be the only way we can reach a "new normal" - a situation where we can do so much more than we can do now. Unless there is some sort of medical breakthrough with respect to the virus then there are going to be problems with it for years to come. Why should we live with increased restrictions for all because a few who could get vaccinated refuse to do so? Surely, if they think of nothing else at all, they should consider those who are unfortunate enough not to be able to be vaccinated? Surely they know this is not a "privacy" issue? It is no more intrusive than showing their licence to drive. It's a licence to live!