The only thing i would say, Les, is that there's a big difference between how a dog behaves in its own territory (which it will try to defend - even against friendly leafleters!) and how they behave in neutral territory.

If a parent is really concerned, they should teach their child not to approach ANY strange dog. And responsible dog owners should have their dogs on leads in public places, and muzzled if there is any risk of biting (either other dogs or people).