I don't even know how one would spot someone that would take a lot of work without actually talking to them first. S:
A year or so ago I would sometimes see a really hot girl hanging outside of one of our school buildings, and I decided I didn't want to approach her because she was wearing what looked to me like a flashy watch. If a woman that age (probably early - mid 20s) in this day and age is wearing a flashy watch, with otherwise nice looking clothes, that makes me assume that either she has a lot of money or is materialistic and won't be impressed by my broke-ass self, so why bother? But that's pretty much the only time I've ever had that feeling, aside from when I had low self esteem as a teenager and assumed any girl would automatically reject me.