Parents I don't know have recently been coming up to me in public places asking for help teaching their children about talking to strangers - which is ironic since I am a stranger to them as well. That being said, let me see if I can approach the topic of strangers and make dealing with them a little less fearful for everyone.
Unfortunately, there are both nice strangers and dangerous strangers and telling the difference is not easy for a child. Ideally you don't want your child talking to any stranger. But there may be a time when your child gets accidentally lost in a public place or experiences an accident while out with friends and needs to seek help from someone they do not know. So, rather than focus on trying to teach our children not to talk to strangers, it is better to teach them to be wary of anyone who acts strangely or makes them feel uneasy whether they know them or not.
If they are approached by someone they don't know, teach them to stay alert keep that person at arm's length, back away and try not to talk to him or her. And of course they should never go for a ride with a stranger that approaches them.
If your child gets lost and must talk to a stranger to get help, have them approach a police officer, security guard or store employee first. If none are around, tell them to seek out a woman rather than a man, or people with children since these types of people are almost never apt to sexually or physically abuse a child.
School age children are not immune either. They should stay in groups when not under adult supervision and should pick out safe spots they can run to if they're approached by someone they don't know or trust. The house of a friend or a nearby school are two good examples.