The kids these days with their low riders and tricked out Honda Accords. They're the main offenders, and then you have your average working Joe who shares the 2 bedroom apartment with 8 other people so he can afford to drive around with a system like he has something to prove.
That would be my guess.
I know exactly what you are talking about. There is a large group of kids that hang out at our local Dunkin Donuts and I could see one of them having these in the back of their car. It's very interesting that the lights glow to the beat of the bass. I wouldn't be caught dead with these in my ride!