see I think it's like finding a paper that does certain comparative work between different kinds of apple pie that says it can determine if apple pie was made by a German, and I said for me to really trust your claims of being able to tell if the pie was made by a German these are the ways I would expect you to test on non-German people who are widely agreed to cook like German people.
Because if you are not testing on people that are supposed to be the most German-like in their cooking then your ability to find the German cooking in a city renowned for its Thai food is not that impressive.
Then in response to your first question I posit that actually it is not possible to identify if pie was made by Germans but probably relatively easy to identify if it was made by people who cook in a German manner. And maybe that is actually more beneficial.
I realize that from communicating with people over the years that things which seem crystal clear to me may seem opaque to others, but I think your analogy is somewhat unfairly structured.
Note: apologies to German cooks and their cooking, although I personally only like currywurst. But I needed something to make the analogy more like what I felt had been communicated, and you were pseudo-randomly picked.