It sounds like this girl needed discipline. Most kids need discipline. When my kid was 4 years old we had a problem with him talking to strangers. Here's how we solved the problem: I had a friend from work drive by the house when my kid was playing in the yard. He lured him to the car with the old "Wanna see a puppy?" story. Then he threw him in the back seat and drove off with him. For two hours he shouted threats at him, like "You'll never see your Mommy and Daddy again!". Then he dropped him off at a distant 7-11. I just "happened" to be driving by and picked him up. Since then my kid speaks to no one. He leaves the house (reluctantly) only for school. He doesn't make eye contact with anyone. He has a slight twitch on the right side of his face but that's a small price to pay for peace of mind.
Thank you. Not many people would agree with you.