The number plates are the only tool available to allow the immediate identification of the owner and status of a vehicle.
They must be correctly fitted to the front and rear (some vehicles are exempt from displaying the front number plate), and they must be clear, clean and visible, and illuminated at night.
It is also illegal to allow anything to interfere with the visibility of the number plate.
Some of this may seem like obvious advice, but it is sometimes advice which is forgotten, apparently especially after a long journey, say from the Far East. That is perhaps the only mitigation, although it is not an excuse, why the Three Kings were fined for driving through the town of Mázarron without displaying the number plates on the back of their floats.
The officers who handed out the 1,200 euro fine needn´t worry about getting coal next year, because no doubt the Kings will realise that nobody is above the law, even visitors from a faraway land, and the police acted correctly.