wrote on Jun 6^th, 2015 at 10:35pm:

There is a big stir in the Mora area as the police have been stopping UK registered cars on the roundabout leaving town. They ask for the driving licence & if its a Euro licence or UK licience they ask for your NIE number if you produce one they take this as evidence that you are a resident of Spain. They then fine you 200 Euro based on a new law that requires one to have a Spanish licence if you are a resident.  >:(

I am not resident as I live between three countries. I have an NIE as I had to get one to buy a property. I use my UK licence as I drive and am based in the UK. My car is UK registered MOT'd and insured and spends less than half the year in Spain.
So an NIE is not evidence of residency.
I also have a Bulgarian foreigners  ID card which is the same type as an NIE , I can't be resident in three countries at the same time.