If you mean it as a sort of "derogatory" description of what non-libertarians think of actual Libertarian beliefs, then that makes sense.
However, in actuality, libertarianism and anarcho-capitalism is very clear about what its core foundations are. And you'll only find the left-libertarians that are very wishy-washy about their beliefs such that each one has their own definition of "stuff I like, and not stuff I don't like".
I didn't mean to be derogatory at all -- I just mean phrases like 'open society' are used in discussion and argument by a large variety of people with a large variety of beliefs, and it always essentially means 'an implementation of my particular belief system'. Libertarianism provided an excellent example because of how prevalent it is on HN -- so prevalent in fact that I had a real life Libertarian pop out to defend it!
However, in actuality, libertarianism and anarcho-capitalism is very clear about what its core foundations are. And you'll only find the left-libertarians that are very wishy-washy about their beliefs such that each one has their own definition of "stuff I like, and not stuff I don't like".