Since having to carry hi vis vests in Spain, Bobaol, we have decided to carry these here in the UK. 
We consider it sensible & we had bought four anyway 
as you need one per passenger travelling in the car in Spain & we often take friends around with us, so we just bring two home with us & take them over next trip. 
The Spanish markets have increased price to 3€ each , noticed this on our March trip. 
You only get one in a hire car so protect yourselves. A hefty fine isn't good !!!