What should we do about "3D Printed Firearms"? (ERRF special)

In this week's special episode from the East Coast RepRap Festival 2019, Tom talks to Keith (as a non-representative of Proto-Pasta) about their ERRF highlight, how the terrorist attack in Halle seems to have used 3D printing to fabricate firearm parts and what we should (or can) do about it. Also, Proto-Pasta's experiences in shipping a filament extruder all the way across the US and whether 3D printer manufacturers should be providing a functional machine to buyers!