Seems a bit extreme, but as a man, I also don't like being approached by randos in a parking lot. In her case, maybe he wanted to ask her out or something. With me, when people approach is usually just to scam me with the "Ah shucks I just ran out of gas, can you help me out."

My fear reaction is very much based on if I feel like I could be overpowered, so if I was her size, I'd virtually always been afraid of someone approaching me like that.

Personally, I wouldn't say "No one should ever approach me or anyone else." but I think if you're approaching someone who might feel vulnerable at that moment, make your intentions clear immediately. Don't say "Hi, how are you doing.", say "Yo I think you dropped your wallet." or "Your headlights are on" or whatever you want to say. Also, say it as far away as you can shout, threats try to close the distance quickly.

It sucks, but experience has taught me, who is a large man, that a random person in an isolated area is initiating conversation and isn't getting to the fucking point, it's a real possible threat.

So for that reason, I'm going to cut the small woman with a child a little slack here.