There was some buzz lately over open parties and the violence that happens in such. A parent is sure to be tempted to arm his kid with self defense products like a pepper spray at least. But that still wouldn't be addressing the problem head on, which is, that teeners are being left on their own an awful lot.
They should be kept busy. That doesn't mean schools should pile all the more homework on them, but maybe they could pile more interesting and relevant homework for them.
But parents can also keep them busy with chores. Kids have to chip in at home because they are part of the family. That teaches them responsibility and respect, apart from reinforcing a sense of belonging with the family first (and not with just any peer group).
Parents should also keep their kids busy with family. Dining together, hanging out, doing things together as a family, having rituals and traditions... all these things will keep children occupied without feeding their insecurities and neurotic needs.
And yes, this means parents have to be home when their kids have friends over. And that parents have to be involved, to a certain degree, with their children's social life.
Teenagers seldom really need a bigger allowance and more time to have fun, but they do need more quidance and opportunities for success.