According to the RCMP, 46,700 "children" (I'm assuming this includes all people under 18) ran away from home last year. Only 46 were deemed to have been kidnapped by a non-parent.
This means that stranger kidnapping is a virtually non-existent problem. Well, at least relative to more probable causes for child injury: lack of sidewalks, parents who smoke, vehicle injury and, unfortunately, parents causing psychological/physical/sexual trauma.
That doesn't mean that kids can start accepting candy from strangers. You don't need to be a kidnap victim to be sexually abused or otherwise harmed.
But I think we need to realise that many children, for whatever reason, are desperately unhappy at home. Often with reason. Send your donations to Child Find et. al. if you want, but be sure your governement is sufficiently supporting child welfare services (Children's Aid Societies, etc...). In many cases, strangers (social workers, school psycologists, shool nurses) may be exactly what children need.