I maintain eye contact, smile, etc if I see a woman looking at me and I've had a few approach me just from that. However, I'm not at the gym to meet women. I'm there working my ass off. I am sweaty, smelly, and usually totally out of breath from doing cardio. Not exactly a pickup scenario for me. If they make it easy then sure I'll turn on the charm but, as others have noted, I don't really want to risk my pleasant gym experience having to deal with an ex lay or gf who is now either stalking, talking $hit, or otherwise making any part of my life miserable when I just want to work out in peace.