Well, as I flew 727s for over ten years and have over 7,000 hours as Captain in the aircraft, just what did you do when the 727s were parked over night and the parking brake pressure bled down?
We never, repeat never, left the parking brake on after being chocked. If for no other reason than brake disk warping.
Do you leave the amp selector switch in the Bat Volt position overnight as well?
You show me a 727 parked on a sloping ramp with only the parking brake on and no chocks left overnight and I'll show you a 727 at the bottom of the sloping ramp.