Word on the street is that satellites and super-sensitive sensors are now tuned to the sibilant hiss of spray cans in a space-age effort to eradicate one of the oldest and most persistent urban problems graffiti. TaggerTrap, a graffiti eradication system being tested in several California cities, uses global positioning system technology, cell phones and sensors that recognize the ultrasonic pitch of spray cans to alert police when vandals begin their work, representatives said on Thursday. Hmmmmm ... Link