I did the same thing in this paper me and Tim Newsham wrote in 1998:

http://cs.unc.edu/~fabian/course_papers/PtacekNewsham98.pdf

Partly it was a showy gesture, but after writing that way for a few days, I came to like how the distinct pronouns made it easy to track "attacker" and "defender" in the narrative, too.

I'd just use "they" now, though.