Battery Terminal Question

[JungleGus]

When working on the car, I usually disconnect the battery - however this is a PITA when you lose the clock and stereo and need to re-program (I have a Pioneed head unit that needs approximately 400 arcane sub-menus to turn off the infuriating demo).

If I were to disconnect the positive terminal in the engine bay, would that cut power to the main body loom as well? My guess is that it would but never hurts to check. Disconnecting the engine loom and leaving the body parts still powered would be nice in theory, but I guess there is a gaping hole in my logic somewhere.

Also - when jumping the car, one can use that positive terminal and any ground point on the engine, correct? May save having to get all the coverings above the battery out, etc.

Cheers,
Gus