Guns, cats, razors, and laws

It basically already is, it just isn't stated as such.

Treat every weapon as if is loaded untill you have personally and properly verified that it is not.

&

Never, EVER, point a gun at anything you do not intend to destroy.

...

Those two are in basically any gun safety rule set you can find, and they pretty much combine into 'Murphy's Gun'.

Note that number 2 there makes no exception for 'my finger wasn't on the trigger' or 'the gun was in a desk drawer' or 'i didn't think it was loaded' or 'i thought the safety was on'.

A lot of people will read or be told number 2 and just insert all those non existent caveats into the rule.