Ive been pulled over multiple times with brand new stock exhaust on a stock vehicle cruising at 55 because the body looked old and rusted and the cops were looking for any plausable excuse. With a real excuse they could throw tickets at you when they get frusterated with lack of other possible charges.
Yes and no. Rich places that can trivially afford to over-staff their PD's compared to the amount of "real crime" to go around are some of the worst when it comes to baseless fishing.
I had a guitar stolen out of my car in the late 90's. It was hot pink, and I was pretty sure that the thief would try to pawn it. So when I spoke with the cop who showed up, I mentioned about checking pawn shops etc. He said "Sounds like a good idea. If you find anything, let us know..."
Completely useless choads...
Case in point: police in my region started cracking down on street racing. Original intention was to deal the obvious danger and noise pollution, but it so happened that after each round of checks they would find at least one DUI, suspended license or even a case of drug possession. Naturally they continued, as street racing is somewhat difficult to prove, but the other mentioned offences are much less ambiguous.
Unsurprisingly people who disregard the law don't just settle on a narrow range of offences.