That's pretty far fetched.
It is only criminals with guns that anyone is worried about. so you're sort of chasing your tail there.
Tell me how this has been effected, like in say UK, where there are still guns and only criminals have them?
Old ladies with nothing on them are robbed. Just because you have an imaginary line that you beleive a criminal will not cross, does not mean they won't hurt the old lady anyway.
It's naive to think they won't.