Yes, the 'Stranger Danger' message may be harmful to children since most children are harmed by someone that they know. Children are taught to beware of strangers and not the people who are most likely to harm them. The overwhelming majority of children who are victimized are victimized by someone that they know according to crime statistics.
Stranger Danger is a simple mantra that kids can easily remember. It will help them be aware of their surroundings and the people around them. The sign of the times includes kids being kidnapped, raped and killed, so being aware of strangers that can harm them is necessary for their survival.
Though the whole Stranger Danger idea is often ignored, it is important for children to know that you can never know what people might be wanting to do to you. Granted, many children are harmed by someone they know, and that's also a problem. But that doesn't mean that Stranger Danger is telling kids not to be suspicious if they think a family member or friend might want to hurt them; it's just letting kids know that you should always be cautious around strangers.
I do not feel the "stranger danger" message is harmful to children. While some may argue this message could have negative social affects and in some rare cases cause more harm than good, it instills a sense of caution in children making them more safe. With pedophilia a very real and constant danger in America, it is better to maintain a sense of caution for the over-all safety of our children.
The "Stranger Danger" message does not harm children. It actually helps them by making them aware of the dangers in an age appropriate manner. Unfortunately, children have to learn these lessons at a young age. There have been too many cases of abductions. Telling children to be aware of bad people isn't enough.