It would be great if someone with the knowledge could make an UI app for setting the default license plate for any (mod) map that doesn't have a set default plate design, perhaps as a drop-down menu of your installed plate designs, and save the setting for the map (locally) until you change it again. As there are many maps without a set plate design, and so many cool looking license plate designs to choose from, it would be a lot of fun to be able to actually use them on the map, so that vehicle configs without a set plate type would then spawn with the plate you have selected for that map.
