I think an easy way to tell if an NT is flirting with you is if they ask you a question about the "real world'. I can't remember the last time I asked a person a question about the real world unless I was trying to "evaluate them" (sounds horrible, but whatever..). If I really was interested in the answer, I'd already know what it was, or I'd be plotting my get away to go think/research the topic.
A good example.
me-"I've heard of the term "haole". What exactly does that mean?"
Hawaiian girl-*decent explanation of the term*
me-"oh, ok."
I had recently spent time researching Hawaiian culture particularly through the lens of white America. I was well aware of what the term meant..and how it was used, so I didn't really need her explanation, but I wanted her....(explanation and/or other things). lol
If I had the balls, and the foresight, I would have asked her if she had ever used the term in casual conversation and taken the opposing position which would have led to a nice little conversation about slurs, the n word, racial realities in America, etc etc but...I was drunk....
Yes, to me this is flirting.