This is a dream of the UK and AU's Christian safety Nazi nanny state program. What better way to keep tabs and control the low life scum that is we everyday citizens than to have a colour coded licence plate system.
Why you could have a plate for rich and poor. That way you can keep the riff-raff out the more affluent areas.
A plate to denote your unending belief in your Christian sky fairy which gives you the privilege of travelling 15mph under the speed limit but only during rush hour on a two lane road.
A plate to denote gays and straights so the Christian sky fairy mob knows who to dog and harass.
A plate for sex offenders to help vigilantes find their targets. A plate left wing liberals to help right wing jargon sprouting parrots to find their targets.