I'm only in my 30's, but I remember in primary school the 'stranger danger' campaign. We learnt about safe houses, marked on the letter box of certain houses (not sure what happened to that initiative) and that in times of trouble, we should be able to approach an adult, preferably a woman in the street and ask for help.
Now I know as a child I would never have knocked on the door of a burka, (does it have to be BLACK by the way) and I sure as hell would not teach my kids to do so. If it's not intimidating, it's certainly not inviting.