I have a 2nd grader and either my hubby or myself picks her up everyday and is home. We live in an upper class/ more affluent area and there are still classmates of my girl who go home alone until parents are home from work. I think it's soooo important for a parent (or responsible family member) to be home w/ kids infant on up to high schoolers. Yes, kids need to be indepent and self suffecient, but there are ways/options to give your kids responsiblity and freedom.
It seems the problems teens deals w/ issues and situations now days that weren't prevelent when I was a teen (and I'm only 28). I think a lot of it has to do w/ the fact there isn't supervision at home, family time, dinner time, too much crap on TV, someone needs to be home w/ kids. Everyone has their own set of circumstances and in some cases both parents need to work. But, where I live, people could afford for a parent to not work or work part time, but they've made the decision the big house, big TV and STUFF is more important to work for. It's very sad for the kids who are being raised by a TV.
Just my 2 cents, no offense to anyone out there.