One of the few times I actually was intrigued by one, was when I saw a car that said ICEMAN
I don't know if there is some greater reference afoot, but I was curious if it was a reference to the song "details on how to get ICEMAN on your license plate" by Don Caballero, a band that is from this region.
https://www.youtube.com/watch?v=d5yeE8NvSSo
However, since a lot of people may see a license plate that says that and scratch their heads, maybe I am an asshole