Generally speaking, StandBy power consumption lowers the overall efficiency of any appliance if it is not used. In an off-grid system which runs solely on batteries, it is even more important to reduce the power consumption to a minimum.
DiVER voltage lanes are generally easy switchable compared to household AC mains (no zero voltage crossing detection, no AC switching, low voltages, no isolation necessary).
If a central controller is present, rather than a bus system:
Any outlet after the circuit breaker could be high-side switched with n-channel MOSFETs. The controller could switch off any appliances in an emergency mode (e.g. battery charge level < 10%)
A timer based switching policy can be made: switch off anything which isn’t needed during the night time.
A standby (leakage) current threshold could be set per outlet: switch it off it the appliance is in standby and uses <50mA. One idea is to use the Rds of the n-channel MOSFETs as a shunt: measure Vds and determine the current. This is not really accurate due to thermal drift and other nonlinearities, but one can decide wether much current is flowing or not. Is it possible to measure very small currents even with low Rds_on? (Multiplexing with a high-gain differential amplifier and a low-pass into one ADC of the controller.)
The tiny DiVER switch mode power supply for USB appliances (e.g. smartphones) is currently based on the LM2596 and the circuit uses a quiescent (standby) current of 20mA if powered with 12V. That may not sound much and is indeed better than most household AC appliances (0,24W). However, every Wh counts if you rely on batteries and I would like to further reduce the standby power consumption without incorporating a hardwired switch.