I don't know anything about high power eBike wiring, and only a little about my bike, but I do know a Bomber has a Crystalyte hub motor, and controller. I think the way it operates is fairly standard, based on descriptions I've read and just looking at what I have.
In my bombers case I'm pretty sure the key switch only turns on the controller, but never has more than a couple amps going through it. Between the controller and the motor is where all the amps are. The battery, and the controller are always potentially hot as long as the battery is plugged in, but there's zero current draw as long as the key switch is turned off.
How all this is accomplished, I can't exactly tell you, but I assume there's only electronic switches other then the key switch..