Poach it hard Dan. It's YOUR park.
I've poached a lot of climbs in my day, but that was private property and it was poaching. If I wanted to go somewhere that these bozos have 'closed' I would simply ignore the closed signs, tape, gates, barricades, and all the other BS these jerks have put up to keep us out, and that ain't poaching: they're our f--king parks.
For the purposes of the shut down 'non-essential' simply means that they are not involved in matters of life or death or public safety, not that the job isn't important enough to pay someone to do it. That being said, if we somehow lost the Dept. of Commerce (for example) during this I don't think anyone would miss them.
And the growth of government and government compensation over the last few decades under both parties has been appalling. It used to be that deal was that in exchange for greater job security and benefits that government workers accepted lower compensation. No more. Of the six counties in the US that have a median income >$100k, four are in the DC metro area, which by all economic measures escaped nearly all the effects of the 'Great Recession'. Go figure. While incomes of most in the private sector have stagnated over the last thirteen years (declined over the last five), it has exploded for federal workers, and especially for the bureaucrat administrators who spend their time shuffling papers. When benefits are included, government workers now make significantly more than counterparts in the private sector.