Don't answer this if it isn't legal to answer, but do you have any examples you can share? I can entirely picture the process, and completely believe that it happens, but I don't have a mental image of what the end result looks like.
We had to run the whole project on a completely separate network from the rest of the business due to the classification of the software, which was driven entirely by a handful of frequencies used in testing; details of which were also broadly available from OSINT sources.
It's the same problem as FAANG collecting mountains of "anonymous" metrics. Pretty soon, you can determine who the "anonymous" user is.