I dont think you can put too much into first day lay these days. Say you meet a woman through work, and you get to know each other over time. It feels natural, pure, and you want to paint yourself and her together in a disney movie. So you end up having sex after escalating slowly over time, and you really want her to be as innocent as possible, as we all want deep down. Problem is, the same woman could have sucked c0cks in a club bathroom within minutes of talking to a guy the week before. How is that? Oh you see, she was drunk so it didnt really happen. (women logic) cute, right? haha. (Based on a true story)
I belive it is hardwired in most of us, even though we might have to learn how to use those powers by messing up a few times. Think about girlfriends or girls you have been with and gotten to know, how often has your slut alert been right? The sum of all those red flags quickly gives your intuition a feel for a person, specially when its a female you have to watch out for and seems untrustworthy. Its quite amazing but also biologically natural.
Are there any attractive girls that havent done one night stands these days? This would not have stopped me from trying with a 10, there are a lot of other red flags to worry about.