One very curious ancap habit is to declare what would actually transpire in ancapistan by looking in some book by an ancap writer. So, for instance, when asked "Would there be IP rights in ancapistan?" they look in Block's work and answer, "Well, Walter Block says 'no,' so, no."
But Walter Block will not be the king of ancapistan, so how he thinks ancapistan ought to work is almost completely irrelevant as to how it will work. To answer that question, we should look to the interests of those with the most money to pay defense agencies to get the rules that they want. And once we do that, we can see that almost certainly ancapistan will have stronger IP rights than we do at present: the large corporations that own those rights today can pay a hell of a lot more to have them enforced and enforced more strongly than they are today, than Stephan Kinsella and his coalition of 50 anti-IP activists can pay to have them done away with.
Incentives matter, but according to ancaps, apparently they will no longer matter in the earthly paradise of ancapistan.