My advice would be to not teach stranger danger as a whole. The reality is that most sexual crimes against children are committed by someone the child knows and trusts. You can teach that there are good and bad people and that no adult should ever ask a child for help (run through the scenarios - lost dog etc.) as well as the other tricks - modeling, candy, games and model responses about running and telling. But at the same time, you need to teach them about private parts and that no one should touch them there except parents/Dr. and that if ANYONE makes them feel uncomfortable, hurts them or tries trick them it is not their fault and they can tell and keep telling until it stops.
It's definitely more likely to be a neighbor, relative or coach than a stranger. We just hear about stranger abduction more often as the other is too often treated as a "family problem."
