The people who developed it will put a chunk of steel in it to trigger airport alarms. Right now they are made of lego plastic - they're good for about 2 uses and they break. At the moment, 3D printers can't print big items. This was made in Austin, Texas. Somehow that does not surprise me.
It's made by Defense Distributors, a non-profit.
http://news.nationalpost.com/2013/05...united-states/
Sad thing is this process can be used to build new ears, noses etc for people who lose them due to accidents or illness. There are good and bad uses for everything.