It's just another avenue. You'd better check your kid's flash drives, pockets, wallets, hard drives, internet databases, IM clients, emails, pillows, closets, MP3 players, game systems, ect if you're going to flip over phones. If a kid's going to do something digital these days, they'll find a new way around anything you try to do to stop them, even if it means just doing it at someone else's house. Better off teaching them morals and such as they grow up instead of trying to iron-fist them.
Or, teach them to be like me and
encrypt all their goodies.