That approach has worked with Sheri, a Nashville, Tenn. seventh grader. Her mother smokes but she doesn't. She tells me all the down sides, because she knows from experience. Kids want to know the boundaries, and they can't know the rules unless you tell them. Be clear about the rules, with no mixed messages.
Children do listen.
They may rebel at first, but when it comes to making decisions about risky behaviors, they value and use clear messages they have been given by their parents. Don't assume children will learn to be smoke-free at school. They may hear about the health risks, but often believe that they are personally invincible. Telling a child how hurt or disappointed you would be if they decided to smoke has more impact than reasoning with them about the health dangers. Peer pressure is often used as an excuse.