this ties in nicely with enf but also girls that are wearing clothing that doesnt quite cover everything they have, and thereby puts them at an embarrassing place.
commando girls in skirts is excellent cus you never know if you might catch a glimpse or not. a friend of mine once told me she was commando ona night out once whilst wearing a mini skirt and although i never saw prrof, i couldnt take me eyes off the bottom of her skirt....just in case. ;)
It's kind of... a universal sign of sluttiness amongst us. Not to mention if there's a breeze, or the place is air conditioned? Fuck being exposed accidentally, my cooch hurts just thinking about it. >:
Sure, it's rare and arousing for guys, and kinda sexy if you know the girl is normally on the straight and narrow. But it's something I'd save for the bedroom, not for public. XD