I was set-up and arrested in 2008 for simply being in a suspicious part of town where I knew an old family friend who fixed my car on occasion.
I was charged with a felony "destruction of evidence" because a totally crooked cop, whom was eventually kicked off the force for messing with hookers, claimed I ate the non-existent drugs, and actually tampered with the swab he used to wipe my mouth.
I was arrested and fired from my job the next week. Eventually, the case was "null-processed" as the cop had been fired for misconduct and the State had no case.
In a life of bizarre legal experiences, it was perhaps the most bizarre of them all, and since then I put absolutely nothing past police, although I do recognize they do a dangerous job of which I would want no part of.
I got messed with by the cops just for being out after dark as a kid. A cop once made my whole family his personal mission just because he caught one of my brothers biking without a helmet.
Well, people who speak up against cop brutality, corruption, etc have a big possibility of being targeted for harassment and intimidation, especially in they live in a small town, or they know who they are in their neighborhood etc.
Of course people without experience with the police force, and without historical knowledge of other incidents and their frequency, often have no idea that this things even happen.
No, he won't recognize them. As he is running the plates and driver's license through the official public computer system, he will also be whipping out his personal phone to run that name through a few private databases, run by ex-cops, with subscription access granted only to cops and ex-cops.
Those databases will tell him, essentially, "This guy created a popular app that puts your job under a microscope. Also, he probably got a bunch of money for it, and may be carrying a lot of cash."
It won't actually say anything about harassing him. That will be entirely up to the investigating officer, and all the other investigating officers that he may have alerted via the aforementioned databases to watch out for cars with the same model and color.