You can even randomly run the VIN if you like. I used to run the plates of cars around me all the time at red lights. Sometimes you get a stolen hit, warrant hit, plates don't match the car, etc.
What exactly do you think the harm is? If you're in public view, your whereabouts and identity certainly aren't private.
I dont see a problem with this, is an LEO is driving around, and they dont have a call why not run plates? especially if its a suspicious looking vehicle?!?!?! so many people will have problems with this yet this is how they catch bad guys. Why not run plates? As said before, they could reveal stolen cars, warrants, all kinds of bad stuff. They could be preventing a serious crime by simply typing in a number into a computer.........since the person is OUT IN PUBLIC. not sure what the issue is here