I've heard many an anecdote of soldiers deployed for months in male-only settings who could smell that a woman had arrived on base. They weren't able to describe what they smelled, or how they knew it was a woman, but they just knew.
None of us used repellent (Chinks could smell it as easily as after-shave, soap, tobacco, and toothpaste); we couldn’t slap at them (noises traveled loud and far at night). So we waited and reluctantly contributed our blood.
and about poor discipline in Vietnam:
Guys were using soap, toothpaste, and shaving cream before operations. They were smoking and wearing mosquito repellent on patrol.