Obviously, they must think it's a feature of some value.
Knowing the country allows an immediate diplomatic protest, threats to withdraw business, and investigation.
The payment is to be within 24 hours, which means that they can act quickly to stop the processing of the data, prevent conclusions from being drawn, etc.
If the signaled country were the US, I would expect a bunch of senators to be immediately called and pressured to look into and perhaps stop the investigation.
Interesting take. It's also possible that it functions as a checksum of sorts for their intelligence operations to identify gaps. e.g., If intelligence has knowledge of X requests from country Y, but they're getting X+5 "winks" about country Y, then it's an indicator of where they need to step up their intelligence efforts.
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