Around here, we normally call it the "slip pitch." I know of a few girls who throw it. A few coaches will teach it, but won't admit it in public afterwards.
And I've personally heard an umpire compliment a pitcher who threw this pitch in a game on her "great change up." Of course, that's what I've come to expect out of a lot of WFC umpires.
I've found that just the fact that the pitcher throws it once, even if the umpire calls an IP on it, some batters are hung up watching for it for the rest of that game.