if they're trying to nab you for something they're going a really roundabout way of doing it and i feel like their efforts could be better used catching someone else or something.
The thing is, I simply don't do anything terribly outrageous when I know there are cops in the area. I know what every police car in my county looks like and where they are usually deployed, so surprises are rare. For instance, these are all the active duty police cars owned by the county (the only police department to have ever pulled me over, a grand total of 5 times):
Ford Taurus (full package, brown) - decals, pushbar on front, lights on roof, most common
Chevrolet Impala (full package, brown) - decals, no pushbar, lights on roof, slowly getting removed from service but still around
Ford Explorer (full package, brown) - decals, pushbar, lights on roof, active service
Ford F-150 (package, brown) - only decals, no visible flashing lights until activated, scores a lot of tickets but the county only has one truck
Ford Taurus (unmarked, brown) - essentially the same as the common police car, but no decals; only spotlight, antennas, and black wheels
Chevrolet Impala (unmarked, brown) - no decals, same visuals but usually have hubcaps, getting replaced
Ford Crown Victoria (unmarked, brown) - no decals, very rare and almost purged from service, typically very bad drivers
Ford Taurus (red; sky blue) - money thirsty undercover mercenaries in somewhat lowkey vehicles, only telltale signs are the black wheels and spotlight
Ford Explorer (unmarked, color variety) - impossible to discern from civilian vehicles, just don't do anything stupid if you see an Explorer