The Libertarian Loophole is exemplified by their position on public transportation, they don't oppose public transportation they just don't want the government doing it - let the free market provide it if the public want it! Except, of course, the free market demands a quick high return. Railways by their very nature are a long term low yield investment generating a return on a scale of 30-40 years, not by the next financial quarter. Something the public can and will accept for public infrastructure. But not business interests. So what the libertarian argues for is a situation where economic strictures ensure it will not happen but they can insist they do not oppose it.