It's a contingency measure. If they dress provocatively enough they won't be killed by enemies, but other things will happen to them instead. However they will still be alive and can strike back when the opportunity presents itself.
Thus it is in your army's best interests to recruit a bunch of women and put them in heart-shaped garters and lingerie while fighting on the battlefield.
People who've needed "a monstah to clobbah dat dere Kirbeh!": 128 http://img23.imageshack.us/img23/15/heartscream2.jpg