Dead Time question

I had always thought.. and from other paranormal shows I have seen.. that dead time, you turn off all power.. not just turn off the lights/fans/etc.. but, actually turn the breaker/s off in the house. If you just turn off the lights.. there are a ton of things that could make sounds.. make things move.. etc etc etc.. so, why do they just flip off lights.. while other shows flip off breaker/s?

Goonies never say die!