If you're asking how the concept of IP might exist and be enforced under market anarchy, I imagine that freeloading would carry the same social stigma as bad manners, poor taste, and obnoxiousness.
Personally, I don't see this issue as being a huge problem. Entrepreneurs such as Gabe Newell from Valve Software have demonstrated that piracy is insignificant. Whether he realizes it or not, he is rendering the issue of IP moot.