Just like omg said: Stuff like this won't make ones life much safer because you can't have your keys or bank cards stolen anymore... it'll only become more likely that you get your hand cut off or your eye cut out so the robber can still do the same.
And if that's not reason enough: No, I won't play into anyone's hands and make it even easier for "them" to track my every step and virtually know EVERYTHING about me. I just ain't sci-fi-geek enough for that kind of stuff... and I don't really find it THAT bothersome to have my keys and cards with me...
