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Harry Mudd approves of this post !
Not to mention that the criminals would need to acquire marketable skills in CAD, materials, and additive-fabrication areas. We're not at Star Trek "replicator" technology where you can just growl "Computer, gimme a gat!" (and then have Majel Barrett's etherial voice nag you for the next half-hour about style, caliber, barrel length, etc ...)
Harry Mudd approves of this post !