Argued this back in a high-school ethics class. Really all they're doing is marking the car as the plate does not change to indicate if the current drive has had a DUI. A better policy is to indicate the DUI on the drivers liscense so that every time the person had to show ID they'd be indicating themselves as a risk rather than the car. Just imagine if your wife got a DUI driving the Z, for whatever reason, now every time you drive it you're indicating that you have a DUI. Yes you could just remove her name from the registration but it's more of a fundamental flaw. Plus it can inspire vandalism against the car. In general a good idea, but in practice a DUI ID or liscense would be much better.
