There is nothing in my home or vehicle that I am willing to "distroy" or even put a hole in.
If you dry fire, you have made a purposeful decision about what you're willing to destroy in the event of a negligent discharge.
Dry fire at the TV?
You have made a choice to destroy that television in case you ever ND. I rather like my 50 inch plasma, and couldn't afford to replace it, so I don't dry fire at it.
For this reason, I prefer to dry fire in my basement, facing a wall that doesn't have anything hanging on it. In the event that I screw up and have an ND, that wall will get a hole, but the round will be safely contained.
The four rules are all about indelibly instilling proper behavior, not splitting semantic hairs.
If this were actually true, or even possible, I wouldn't own a gun at all.
It is true, insofar as a tremendous number of negligent discharges with tragic outcomes are the result of someone screwing around with a gun that, after the event, they swear up and down was not loaded. If you assume the weapon is loaded at all times, you have prepped yourself for the worst case, and hopefully engaged in behavior that will help to mitigate that worst case if it ever comes to pass.
3. Keep your finger outside the trigger guard until your sights are on the target.
This is probably a good suggestion, actually. Rather than telling the shooter what not to do, which can lead them to fixating on "trigger" you're telling them what the actual proper behavior should be.
One of the things that has always stuck with me from reading Lanny Basham's book is that the mind doesn't see a negative, and will tend to fixate on the x when told "don't engage in x behavior." His suggestion is that you should always phrase things so that you are told what the proper behavior is, which gives your mind something positive to fixate on.
How about those gun owners that live in apartment buildings or condos, where they're literally surrounded by neighbors upstairs, downstairs, next door, and across the hall? Which neighbor or neighbor's property should a gun owner be "willing to destroy" in the event of an ND or AD whenever he/she handles a firearm?
That's a choice that a person in that situation has to make, and it would behoove them to put some serious thought into just exactly what they're willing to do to mitigate tragedy in the event of an ND.