Thinking back to my school days, I remember one of the guys, a well-educated, pleasant, intelligent guy, got big into "tagging". He used to call himself "Rez", I think, and he and his friends called themselves the SBC, Stealth Bomber Crew.
I have no idea what their motivation was, what they got from it, why they did it, but i know that they did it a lot. They must have been around sixteen at the time, and were not deprived kids in any way.