If the people writing the laws wish it, then yes, technologies should be expected to do so. In practice, your gun detector wouldn't solve all gun crimes, just l

If the people writing the laws wish it, then yes, technologies should be expected to do so. In practice, your gun detector wouldn't solve all gun crimes, just like crypto regulations don't stop all crypto crimes and littering regulations don't stop all littering crimes. They just reduce those crimes to the point that society seems reasonable.