Oscar - your mention of the NPS billing Bob Thurston leaped out to me reading through this thread again:
One of my other "lives" is that of a competitive rules official for another national (sport) governing body. The NPS apparently doesn't take too kindly to any sort of encroachment, or at least not without getting their fair share of the "pound of flesh."
A particular event organizer was informed that they would NOT be able to have their triathlon bike leg go out onto a stretch of the Gulf Islands National Seashore, forcing them to double back on a three-mile stretch of their bicycle leg. Two-lane road...1,200 athletes...what could possibly go wrong?
While the flora and fauna were most likely not irritated by the incursion of human triathletes onto their front yard, it placed some major safety/fairness concerns in the hands of the CRO's working the event.