[Natsu]

I often drive home from work very late at night and I've been pulled over and followed for doing absolutely nothing wrong. I think one said my license plate was dirty. They let me go and told me to have a nice night when it was clear that I wasn't doing anything wrong, though.

[tptacek]

The point is, the police are (usually) required to have cause to stop motor vehicle drivers, and if they arrest you for DUI after stopping you for no reason, you have grounds to challenge the arrest.

Obviously, "grounds to challenge" is no guarantee that you'll be acquitted or have charges dismissed, and obviously the police can and do manufacture reasons to pull drivers over, but the requirement to have cause creates a disincentive to do that routinely.

Which, my point was, was one reason one might experience stricter detection of DUI's in another country.

[Natsu]

Oh, I agree with all that. I'm just saying that you can be stopped for no reason even in the USA. I believe they call these pretext stops.

That said, I didn't give him a hard time so the cop remained very friendly the whole time and I didn't have any trouble after getting stopped.