Again, a good (in function) hammer, knife, pen, or gun does not care who holds it, it will act to the maximal best of its specifications up to the skill-level of the wielder. Anything less is not a good product. A gun which checks owner is a shitty gun. A knife which rubberizes on contact with flesh is a shitty knife, even if it only does it when it detects a child is holding it or a child's skin is under it! Why? Show me a perfect system? Hmm?

> A gun which checks owner is a shitty gun

You mean the guns with the safety mechanism to check the owner's fingerprints before firing?

Or sawstop systems which stop the law when it detects flesh?