Stingray manuals and law enforcement license agreements are strongly worded to require parallel construction. Start googling from there and discover a whole world of tinfoil.

No not really, as its more something I've read about on/off over the years, in a variety of articles, and I am by no means an expert.

The wikipedia article on the topic does have some decent links to specific examples from reputable sources and is probably a good place to start - https://en.wikipedia.org/wiki/Parallel_construction

Look at news stories of unusually large narcotics busts attributed to a random leo pulling over a car for a traffic violation.