You know, I'm not sure. It WAS on public land (a park), and Running Fit did bring out their van o' goodies, but I don't think it was insured in any way. I was kinda thinking of that, like, what happens if someone has a heart attack and dies? But, again, it's free, a group of running freaks just getting together. What I liked is that the organizers did at least have that sign up sheet so that they could make sure someone wasn't lost out there. They checked to make sure everyone finished.
It would be unfortunate if litigation came in the way of something like that. I'd say just go for it, put the word out and do it in a public place.
John