The metal gun with 3-D printers

I found this article about 3-D printers in CNN.
     In November 9th, Solid Concepts, a company of manufacturing in Texas has revealed that they made a gun from stainless steel that has very similar looks with the real hand gun to warn the dangerous of 3-D printers because 3-D printers will let criminals make their own weapons.
     The first time I heard about the 3-D printers, I was very excited because we will be able to create anything we want by using the 3-D printers if we have enough materials to produce something. In addition, the price of them may be higher now, but it will become cheaper someday. So we can expect the age of owning the 3-D printer by myself. However, this new technology has some problems such as this article, so we have to establish some rules to use the 3-D printers safety and peacefully. The 3-D printers will be very useful and so I do not want people who contrive to use them in wrong way.
     Now, I wanted to ask you that 1) What did you think about the 3-D printer? And 2) Should we make some rules about the 3-D printer? Why or why not?