I was my parents’ dedicated cop watcher since I was 8, and this is definitely a big one that a lot of people overlook. It’s one of the easiest features of even an unmarked police vehicle to spot from behind if you know to look for the folded light’s mounting hardware. My wife is always surprised at how quickly I can spot a cop from long distance, and it’s often because I spot something strange sticking out of the drivers’ side mirror.