Lets step in to the time machine and go back, go way back (actually just a little) to 2002. Iraq had Weapons of Mass Destruction. Everyone knew it was just a matter of time. Even Bill Clinton and Al Gore stated that he clearly was close based on what they knew.
So the "Precautionary Principle" required that we needed to invade Iraq because better a conventional war today than a nuclear war tomorrow. Very sensible logical idea except... It turned out there were no WMDs and that we are incapable of winning in Iraq.
Ok, lets hop into the time machine again and go back to 1972 to the Club of Rome study - which remains the best selling environmental book in history. Where they predicted that we would shortly run out of 10 critical raw materials which would devastate economic growth. Once again the "Precautionary Principle" requires government to step in and address this except... 9 of the items are now cheaper and more plentiful today than then (the 10th is oil). Governmental intervention would have turned a non-problem into a problem.
Yes sometimes early intervention would cut a problem off early. Global warming is a clear case where action 10 years ago would have been a lot easier. But hindsight is always 20/20. We don't know today which of the potential problems we face will become a real problem tomorrow.
Which brings us to Open Space in Boulder. Yes overuse of land causes degradation. As do an excessive deer population, prairie dog invasion, global warming, pollution, rain, sunlight, and life in general. The goal cannot be to return the land to it's original state as that would require all of us leaving North America - not going to happen.
And people pay taxes for Open Space to make use of it. Yes that includes looking at it. But it also includes using it. Walking, running, taking the dogs out, even the obnoxious high-speed trail bike riders. We need to accept that there will be minor degradation due to use. If nothing else, we will have hiking trails where many people follow the same path.
So how do we know how much use is too much? Well, the only way unfortunately is to allow regular use and then scale it back where it starts to have a severe negative impact on the land. As much as some experts like to pretend otherwise, there is no way to predict this accurately up front.
And with rare exceptions, when the use does have a severe impact, the answer is not to close off all use, it's to appropriately scale back use as necessary. To disallow certain uses that cause the most egregious harm. To find the right balance.
The last thing we need is the "Precautionary Principle" locking our Open Space up in a glass case. What we need is a focus on "Maximum Appropriate Use." It won't get the support of PLAN Boulder but it will get the support of the other 98% of Boulder.
What we don't need is a George Bush, someone is "The Decider" approach where extreme measures are taken to stop something that might happen.