> The obvious problem: you cannot reliably detect firearms from geometry alone. The obvious problem with this argument is that in just the medium term, world-model style AI will get good at this task, but having big brother pre-approve every print will still be bad.
How? The printer only ever retrieves G code for individual parts without any knowledge of what they are going to be assembled into. There is no viable way to solve this classification problem on this kind of incomplete data, is there?
It depends how you define the problem. Certainly a human can look at a part and say "that's a lower reciever" but you probably can make something that functions as a firearm exclusively from inconspicuous parts. For the more limited case, an AI can definitely be trained, the broader case is likely unsolvable.