It's just about as dumb as putting everyone's name on stickers and putting them in the car window. "Hi, we're the really stupid family from this town that you can look up in the phone book or the Internets any time you want."
Imagine the fun. Here's the family traveling in another town and a quick phone call to someone in their town: "Just spotted a place to break into. Their sticker says we're the Morons from Idiotville and they list mom and dad's name as Fred and Wilma, so should be easy to find."
The same with putting a dog's name on their doggie shirt. "Hello little girl. Your beloved pet whose name is Fluffy is hurt and needs you right now!"
What got me going on this was seeing all the customized Halloween shirts at Cafepress. It's bad enough to display family and pet names on your car windshields, but it's downright stupid to send your kid out among strangers saying "My name is your future little victim because you know my name now."
Before people get all excited and tell me I'm being paranoid, get on that internets thing and do a search for level three sex offenders within a mile of your home www.familywatchdog.us/ and then tell me you're comfortable letting your kids wander around branded with their names.
Instead of making it easy for predators, send your kids out wearing this and train them that their names are private and available only to a privileged few. It may very well save their lives some day.