Sad. I believe you are correct. I saw all of two non Army/military nurse females in RVN. One was the daughter of the Special Forces B Detachment CO located in Ban Me Thout. I believe she was visiting? She may have been his wife? The only other civilian female I saw was a senior officer’s wife in Nha Trang who ran a gift shop with items bought in Thailand. I recall buying my two sisters plus mother black star saphire pins after R&R. Lastly, I was with the Army nurses at the 93rd Evac in Tuy Hoa in late Apr 69 until being medivaced to Camp Oji Japan with two GSW’s. I never saw any other US women there.
That oughtn’t to apply here, though, since SHE was not cooped up in the prison 24/7 like a ship or a military base.
Occam’s Razor suggests she had a bad-boy fetish and that’s the size of it.