I live in Austin, and I find out that this happened via HN! Still, cool effort. I'm wondering what the demographics of the players was, for example age range.
Early 2000's, we'd regularly play organized games of CtF upon the capitol grounds — it was incredibly entertaining, even if you weren't actually playing very much (became sort of a HS social / mixer). Typically only a few dozen serious players, but often 100+ participants.