Earlier quoted context omitted.
Does he really have to own the gun or does he just have to declare his camera as a gun?
This. The GP got it wrong. The suggestion was to use something "sortof" gun-like to declare that the case contains a weapon, so that the TSA has to list (and treat) according to the rules for these things. The one giving the advice said that he has a "starter pistol", which google explained as a gun that you use to start a race etc.. Not a real weapon. Others suggested a flare pistol (Dangerous? Sure. But not a 'weap…
The article referenced, which I read, had this:
"Then someone has the brilliant suggestion of putting a firearm in your camera-equipment case"
Matt Brandon (the blogger referenced) had the genius move of using a starter pistol rather than a handgun.
However, it is still sad and slightly scary to me that the solution to protecting your property during a flight is to pack it with a weapon or something that looks like weapon.