Majority of Battery Disconnect Switches do NOT disconnect all loads.....
Parasitic loads can be LP/CO Detectors, Radio, Clocks etc
Many folks turn it off expecting ALL DC is shutdown only to return weeks later and find batteries DEAD
Really depends on HOW the disconnect switch has been installed.
Don't 'ASSUME' it shuts down ALL DC
Look at the Battery POS Post....does it have just one large cable connected to it or does it also have several smaller gauge wires connected.
Smaller gauge wires probably do not go thru disconnect switch