Really? so they have 3d printed plastic bullets as well? you do know that bullets are metal casings with metal projectiles that easily are detected with current metal detectors.
My pants buttons have about as much metal as a bullet has in them and pass metal detectors just fine. Given that most of these plastic guns can only fire a few shots reliably (before becoming structurally compromised), I'm skeptical of why anyone would take any more bullets than that.