It's going to be so hard for them to track this in the future it will never be a "real" law. It will be a law in the way that piracy is illegal.
Thanks josh for bringing this topic to the board. It fascinates me like Bitcoin does.
Essentially, what we're seeing is a decentralization of many things (money, manufacturing, content production and distribution, etc.) due to technology. And the internet will allow people to globally share all this instantly.
3D printing is going to bring about a "crisis" of "piracy" in the future. I put crisis and piracy in quotes because I don't think it's a negative thing, but it will certainly be portrayed that way.
You will see 3D printing vilified because it will "put people out of work" or "destroy American manufacturing" or some other shite. And you will see companies bitch and complain because now Joe Blow can print the part he needs for his car instead of having to go buy it. And they will call it "piracy" or a litany of other menacing terms to propagandize against it.