I maintain the help documentation for our software products, and no, I've never put any little nuggets in there ever. Honest.
Some of them are subtle, and you need to look at the screenshots of the example datasets being processed.
Some, less subtle!
Aside from little nuggets I throw in, there's also the issue of example datasets.
There is data which is publicly released, which I can use.
But sometimes, I need to illustrate a specific unusual issue.
I might need to fake data to do this.
My faked data might have to be based on real-world data to illustrate the point.
The specific sub-division of the industry that I now inhabit is very small indeed, and the various consultants who use our software all know each other and all have moved between all the major oil cos.
The example datasets I Illustrate are all anonymised and adjusted from the originals, yet there are several of our customers who can look at the examples and say "hmm, that looks familiar..."