There were a lot of women criminals
I've only seen a few episodes so far, but in nearly every one of them, there is a woman that is either the main criminal or a conspirator. In one episode, both main criminals were women- disguising themselves as men to commit robberies.
Contrast this with Westerns of that TV era that rarely had women villains.
Joe "We're authorized" Fontana: I can do this all day, Mitch. How about you?