The ID is the part I would keep. Without it the record dies at the first trade, exactly as you say. I would only go one step further: the ID cannot be a row in one app's database. It has to be a signe...
That is the difficult part for me. Figuring out the country from a photo alone would be very hard and I do not have a database that could reliably do that. That is also why I said the project has been sitting on the shelf for a while. I was not sure there would be enough interest to justify building all of the infrastructure around it. The signed ID idea is interesting though because that could make the record survive even if the app itself disappears.
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