Males of course can't notice if women adjust clothing when they aren't looking, if they adjust clothing sufficiently often then it's as if they adjust clothing whenever you're looking
That plus subconscious monitoring of nearby males and how they move, if you're a woman roughly speaking if one is in your blind spot it's sufficiently probable he would be using that chance to look at you (or parts of you).
Women usually have better peripheral vision than men. Also we hear and smell many more things, than we consciously notice.