"Stay away from strangers" is a popular warning to children to prevent abduction or exploitation. The term stranger suggests a concept that children do not understand and is one that ignores what we do know about the people who commit crimes against children. It misleads children into believing they should be aware only of individuals who have an unusual or sloppy appearance. While occasionally a "stranger" will abduct or exploit a child, many children are harmed by people who have some type of familiarity with them.
It is more appropriate to teach our children to be on the lookout for certain kinds of SITUATIONS or ACTIONS rather than certain kinds of individuals.