Yes you are quite right in what you say pondgirl,
This applies to all  cars and ones not in use , just general sitting there gathering dust here in Spain.
But the problem will be for some  people who have a
Rural address or a Po box address or don't check their mail box on a regular basis that the fines are then
returned to traffico and resent , backwards  and forwards like a yo yo,
So these fines will go up and up ,
I suppose there are or will be checking on their computer base ,
Then send the fines out by registered post just an educated guess.