Re: Fishing Expeditions & Dreams of FOSS Alternatives to Privacy-Violator Waze
"Which means that they are allowed to pull anyone over, at any time. And they do."
Which, to some extent, is true. But they're usually too busy to just pull over a random car. There are certain things attract the attention, get their "Spidey senses" tingling, lead them to decide to stop a car and investigate further. And in many cases it proves fruitful.
We don't tend to see road blocks in the UK where all vehicles are checked. Most common are truck checks or maybe vans, but its rare for cars. OP uses the term "DUI", driving under (the) influence, the common term in the USA, you know, land of the free, home of the cops are out to get you.