The question might be more about marginal cost. What would it cost a militia to outfit themselves with a thousand illegal guns, versus the material and power to print a thousand guns? If printing is cheaper, how much more likely does this make the creation of militias?
I would much rather there be no 3D-gun-printing situation... but I'm not sure that I'm too concerned about militias, albeit only given the current state of 3D printers. There's a weird race between the capacity to manufacture anything at any time, and the ability to harvest sufficient energy to make the former not-so-important... and the former is in front right now. That is for sure a kind of scary thought. Plastic-gun-toting militias are probably not a big deal right now, but yeah... what if 3D metal printers become as prevalent as mobile phones? Hopefully some balancing technology will have also become so prevalent. If not, there are companies that make amazing tents, and there are lots of mountains and woods... :)
