I studied abroad in Madrid my junior year of college. I found the youth fashion in Madrid to be MUCH more extravagent than here in the United States!
The teenages tend to be very trendy, stay out late, smoke cigarettes, punkish?
My guess would be that to advertise a certain type of sunglasses to them, it would have to be something fun, and very exciting!
I can not speak for all of the teenages in Spain, but this is what I can remember! Hope I was of some help!