I hear what your saying, and yes, it is just me being a dinosaur. It is definitely a me thing. I've even added QR Codes to my son's monthly invoices that I send out on his behalf, and it works well. He also has a laminated QR Code for when customers don't want to pay him by cash. So as you can see, I'm quite au fait with the technology, in fact in another life (over 20 years ago) I was part of the team evaluating the use of 3D Bar Codes (now called QR Codes - at least, they look like the beasties we were developing) for the MOD.
Maybe when I eventually upgrade my 8 year old Smart phone, I might feel more at ease with the upgraded security, and move into 2024

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As for your caddies, it wouldn't surprise me if you could tip many of them via QR Code. Creation of the code is simple, and anybody with half a brain can do it - I did.