As Pat Rogers always said, "Policing is regional".
It is only recently, through my participation in some of the good Internet forums populated by intellectuals such as you all, that I have come to realize the significant differences in law and procedure and custom from one state to another.
Around here (Wisconsin) unmarked cars have been common since before I started driving (which was 1975).
We get the occasional incident involving a police impersonator but I get the sense that such incidents are more frequent in other parts of the country
Non LE here.
I saw one of the black ones last week while in NH on business. I thought it was an SRT the way he took off up the ramp. Half a mile later he turns into a crossover and I note the markings. He did not activate the lights when he turned in, but I can imagine it’s pretty noticeable. Sitting in the grass median it was actually more noticeable than the traditional forest green and beige trooper vehicles.
The ‘Black and white” theme is applied with various degrees of execution around the country.
I prefer them conspicuous for all the reasons outlined here.
It seems that so-called speed traps are not as prevalent as they once were. When I lived in Alabama, one town became notorious for these. The governor put up large billboards on the main road going through there. In the past when traveling between Texas and Mississippi, I would use a radar detector even though I did not exceed speed limits. This habit showed my cautious nature.