Then five minutes later, someone figures out how to make a 3d printable gun that bypasses the gun detector on the 3d printer. It’s not like you’re printing a whole gun; you’re printing parts, most of which look nothing like a gun. How hard would it be to design an algorithm that takes a gun part cad file and then adds a bunch of extraneous pieces to it that can be easily removed? Just keep adding extra crap until the system no longer detects it as a gun part.