What can parents do to protect their children from predators?

I am a very protective mother. Though I allow my kids to play outside of our house, I see to it that they will not go out beyond the fence. If I'm not around I let my husband or the house helper to watch over them. When they are in school, I always tell them not to go outside the school premises. They should report to their teacher if they can detect any unusual people that have gone in the place. When we go malling, I always instruct them not to talk to people they don't know and would pretend they know me or their father. They should not be allowed to go to CR alone especially in public places. There will be time that they will be left alone in the house. Tell them not to open doors when somebody knocks. Children predators tend to befriend the children and pretend they are a friend of the parents. Let's work hand in hand. Report to authorities if you know somebody who is a predator.