[YmMot]

That idea and even the scenario you describe has actually been used numerous times in action movies (though admittedly usually using a different principle like fingerprint reading), including the James Bond franchise. For example, in License To Kill Q invents a gun with a palm reader that can only be fired by the person programmed in. It has green lights on the grip.

[Wingman4l7]

The first example that comes to mind for me is a scene in the 2007 movie Shoot 'Em Up; the protagonist's workaround for using a dead henchman's thumbprint-verified firearm is to use their severed hand (of course).