As the watch scouts the neighbor's house, Bob learns that Chelsea is at an unsupervised party with Jason.

"Instead, talk about the specific behaviors you don't want her to do, such as going to an unsupervised party or hanging around the mall," he continued.

Getting parents to pledge as a group not to allow unsupervised parties in their homes is another idea gaining ground.

Their unsupervised parties can encourage excessive drinking.

For parents worried about their teenager's possible substance abuse, online activity can seem as hazardous as a boozy, unsupervised party.

"In past years, kids went to motels and unsupervised parties at people's homes."

The police say that the unsupervised parties also offer young people a place to experiment with drugs, especially the psychedelic Ecstasy.

In one episode, at an unsupervised teen-age party, one couple disappears into a bedroom behind locked doors.

Parents often encourage the very behavior they eventually question, as they vicariously meet many of their own needs by promoting extravagant and frequently unsupervised parties.

Last month, nine high school football players were suspended from school after they attended an unsupervised party where alcohol was served.