Oh for God's sake. When you pick up the gun, you rack it - so you can shoot it. If the sound scares someone, it is a nice side effect.
It is not a 'tactic'.
You also train for the possible. Maybe most burglars are cowards compared to the heroes of the Internet. Some might be Platt or Matix, the DC Snipers or the North Hollywood bank robbers.
The only sensible plan for the home owner is to rack the gun immediately and not try to make a display of it from an exposed position.
This is really not rocket science. You don't make this sound as a warning. Duh - 30 year veteran of law enforcement doesn't drop tactical IQ points on you. Bah. I know lots of veterans and instructors - they don't advise racking as a warning.
Warnings are verbal, clear and from behind cover.