"A Democratic state lawmaker from Los Angeles pushing a bill that would require anybody who constructs a homemade firearm to first obtain a unique serial number or other identification mark from the state attorney general’s office. Within a day of assembly, the number or mark “shall be engraved or permanently affixed to the firearm.”"

Anticipating 3-d printer guns?

Yep, it's now possible.

Well, in that case -- and only in that case -- the desire to regulate makes sense.

Can you imagine if anyone can just print a gun, shoot somebody, and then leave the gun at the crime scene? With nothing to demonstrate whoever owned it, we'd only be able to rely on DNA CSI work and surveillance cameras and smartphones everywhere...

With the regulation, criminals still wouldn't label their guns, but at least we'd know if non-criminals' guns were used in crimes.

Exactly!  We think we have problems now, with untrackable guns, stolen guns etc, add to that guns that don't even exist, that can pass through a medical detector, undetected.  Not good, we have enough problems already, don't need to add more to the mix.