I think stranger danger is over emphasised. The chances of a paedophile kidnapping your child or attacking your child are, thankfully, slim. Further, if a paedophile does target your child, it is unlikely your child will be able to do a whole lot to avoid the situation. A committed paedophile would, sadly, have a whole load of arguments, enticements, threats, etc (in a grooming scenario) at the ready or will just take advantage of a situation that the child has no control over (in an opportunistic scenario).
In both scenarios, I am not sure what a child can do to protect themselves.
I remember when I was in infant school, my mum was in hospital and my Dad was working abroad and so we were instructed to get a taxi home. (My grandma who did not drive was waiting for us at home). We were given clear instructions about where to wait for the taxi and what the taxi driver's name would be. On the day, a taxi driver walked up to me and said, "John can't come to collect you, so I am here instead, your mum says to come with me." It was all innocent and true. As I walked to the taxi, all I could think about was, "we are being kidnapped by a stranger, this is not the plan, where's John? who is this person?" BUT I also felt totally powerless to do anything other than get in the taxi with this man, who was taking charge. I felt sure I was doing the wrong thing, but I couldn't do the right thing, because I was a polite and shy little girl who did what adults told her to.
All to say, knowing about stranger danger does not protect against strangers.
I think there's alot of understandable but unnecessary (statistically speaking) fear but telling children these fears only puts the responsibility onto the child. It's a responsibility they do not deserve and most probably cannot take on. Nor should they, IMO.
More helpful to teach what inappropriate touching is, as tjhis can take place in a family, school, scout, church, whatever setting and is, sadly, more likely than stranger danger threats.