Sad story, unfortunately you can be approached almost anywhere. You have to be vigilant.
Your most effective defense is Situational Awareness and a Plan. What happens if...?
Something like what happened to us on a Saturday night in the Newmar building 10 parking lot. We were settling in for the night waiting for service the next week at Newmar. An attractively dressed female gets out of a car stopped in front of our RV on a Saturday night and approaches our RV. After knocking on the door, she asks what I determined to be an odd question. The question was innocuous but out of character for the situation.
First thing we did was turn on all outside lights, then look around and assess the situation. DO NOT open the door.
We pulled the shade up to look at who knocked and then respond with a simple "no, we can't help you".
Basic situational awareness is a top priority. Know who and what is around your space.
You might ask how I knew how she was dressed and how I knew there were other occupants in her car?
It is my habit to investigate anything that approaches my position, especially when we are in an unregulated space at night. I heard the vehicle approach on the gravel and looked out the window to see her exit the passenger side. Thankfully there is some ambient light in the parking lot at Newmar. Noted Color, Make and Model.
Thought it was odd that she was dressed in very nice office attire on a Saturday night in an industrial complex parking lot. We were in the Lot with only a couple of other RVs waiting for service the next week.
Thankfully when she realized we were not going to open the door she retreated to her vehicle and they departed the area. However, I did not sleep well that night.