Casually asking someone about human trafficking

So I had a night shift at work one night. As I was walking out, I noticed another coworker walking out. She said hey, what’s up, and we walked together for a short bit. As we got closer to the parking lot, I said overtime there’s usually a bunch of cars parked in the parking lot across the street. I was talking about how the cars were parked in an unusual way. Her first question was, “Are there any human traffickers over there?” My response was, “Why do you think that? There’s usually a bunch of cars parked there, cars drive by like this one and the other one. (I was pointing to the cars and the car passing by). We said our goodbyes and her car was parked next to mine. So I sat in my car for a bit until she left. I think she was waiting for me to leave, but I had no intentions on leaving that parking lot until she had. I started my car and my lights turned on, which probably startled her, so she left and I waited until she was out of sight. I’m just wondering why she asked that, and if that was a red flag.