Today, July 1, most countries in the EU are experimenting with the use of a QR code to accesss events, transportation, etc. in the EU.
These QR codes are not available to residents outside the EU. This has many people of this board worried. (Except, it seems Californians who get a QR code from their state. It won't work in the EU but they don't want to know that.)
Let's put this in perspective because many are only looking at this through their own eyes rather than the big picture.
The EU countries came together to agree on a format where the QR codes could be read in each others countries. (Most travel in the EU is from residents of other EU countries.) That would be like every U.S. state coming together to agree on a similar system that conforms to Europe. If the U.S. federal government would do this it would be easier but that's not going to happen. So now every state would have to spend a lot of money to help you spend money outside the state and the country. Why would they do that? They want you to stay home and spend money in your state? Could you imagine the next time a governor who okayed this ran for relection? His/her opponent would be screaming how that incumbent spent your tax dollars--speaking to those who don't travel-- so the priviliged could have fun in Europe. (Only 12 million Americans visitied the EU in 2016. That's 4% of the population.)
Now let's look at this from a bigger picture. In 2018, there were 168 million arrivals into the EU from non-EU countries. I couldn't find how much was spent but it has to be in the tens of billions of Euros. However, if each one spent 1,000 Eruos that would be 168 billion Euros.
Do you really think the EU is going to say to those 168 million that if your country doesn't conform to our system and generate QR codes that you can come here but you can't do anything? You can't eat in restaurants, go to museums, bars sporting events, etc. How many people would still go?
Or, is it possible, that the EU will come up with some type of Tourist Covid Certificate, similar to what they are doing with ETIAS, where tourists would register and then have a QR code generated? It would have to be a choice of digital, an app and on paper for those who don't have a smartphone. It's not foolproof, nothing is, but it would be easy to do and would work.
Most of the numbers I quoted came from the official EU website.