Fair point, but I imagine disconnecting is mainly to avoid live HV wiring throughout the vehicle, and thus reducing risk of catastrophic shorts or arcing. If t

Fair point, but I imagine disconnecting is mainly to avoid live HV wiring throughout the vehicle, and thus reducing risk of catastrophic shorts or arcing. If the aux supply is near or in the battery, leaving that connected would while the rest of HV is interrupted would probably not cause any notable increase in risk. At the same time, vehicle fires have been caused by a shorted auxillary battery (I have personally experienced an entire industrial building burn down because the 12V battery in a parked ICE car shorted and went up in flames), so I imagine only having one battery to worry about is a risk reduction.