A few years ago in Austria a new number plate system allowed the the region indicator (eg' I' for Innsbruck) followed by almost any name you wanted. My friend Rudi was too late to get I Rudi. But you will see lots of cars with names or , I Audi ,I BMW etc.
The number plate is actually identified to the owner not the car. They can use the same number on two different cars - eg a summer car and a winter car .If one is laid up in the off season. It used to be quite common to have a nice car for the summer and an old wreck/4x4 for winter.