Anyway, we have all seen these scenarios before....
Situation #1: A SWAT team or hero approaches a door or barrier, beyond which are some heavily armed and ill tempered bad guys. The anticipation builds as you can see each member of the team ready for the assault..."lets go!" says the leader and racks a shell into the chamber of his shotty
Situation #2: Somebody levels a shotgun at a person or persons threatening to "cut them in half" or similar...somebody makes a move toward the gunman and then he racks a shell into the chamber to show them he means business.
Situation #3. Heroes talking in the middle of a gunfight about how well or bad the fight is going..get ready to head back out...one hero (with a shotty of course)..says "OK, lets go" and racks a shell into the chamber.
For crying out loud Hollyweird! Enoungh! I know the folley guys (dudes that make the sound effects) probably love to do that shotgun-racking-sound thing and its a way to emphasize action on the screen but for heavens sake, it makes no sense at all.
For one to walk around with a weapon without a round ready and chambered in a hostile environment is just plain stupid. Shotguns have manual safeties on them like most other weapons and a trained operator keeps his finger off the trigger to begin with, such as the "elite" shooters you so often portray.
A tactical shotgun course will teach you that, unless you observe or assess a target needs to have a different load employed upon it (eg. you have 00 buck in the tube and the target needs a full slug to dispatch it), you chamber a round immediately to ready for the next target and reload as you can tactically if the situation allows. Most duty/combat shotguns (save for the AA-12 and the like) such as the Remington 879 or Mossberg 500 are limited to 6 - 8 rounds normally. Every effort must be made to manage ammo stores in order to operate these weapons and maximize firepower. By leaving a empty casing in the chamber takes one more ready round out of the weapon.
Lastly, and sadly, this trend is also crossing over in movies to where you see people drawing their sidearms and racking rounds into the chamber as well...not that carrying in Condition 3 is bad or anything, but as a "professionals" so to speak in the movies they would most likely carry in Condition 1.
Just some food for thought, here are the "Conditions of Carry" as laid out by LTC Cooper...yeah, they are directed at a 1911 but if you read into them you can apply them to almost any weapon or weapon system...for example, I know of no knowledgeable shooter who would carry a 1911 in condition 2, especially in pre "series 80" models with no firing pin block, but that would apply to a modern revolver that does have a transfer bar or other firing pin safety. Oh yeah, shotty with round in chamber, safety on? ...Condition 1.
The Conditions of Readiness from the late LtCol John Dean "Jeff" Cooper:
Condition 0 - A round is in the chamber, hammer cocked, and the safety is off.
Condition 1 - furthermore known as "cocked and locked”, means a round is in the chamber, the hammer cocked, and the manual thumb safety on the side of the frame is applied.
Condition 2 - A round is in the chamber and the hammer is down.
Condition 3 - The chamber is empty and hammer down with a charged magazine in the gun.
Condition 4 - The chamber is empty, hammer down and no magazine is in the gun.