After I had that conversation and went home I was able to find the legal wording, or maybe I read it on the board at the trailhead. I just spent a few minutes googling but turned up nothing. But I lack the effort to continue as I don't really care, just posting up a personal experience. No fines or tickets happened to me, just a simple conversation.
Things could be different now or that guy could have been being a jerk. Doesn't matter to me either way.