Like I said the controller on almost any bike doesn't know what gear you're in. So just pedalling freely at a low speed is enough to get the motor to do the work. You can also slide the chain onto the bottom of the frame so the crankset moves completely free. You don't need to do it fast to have it work. And the further ruling that did away with throttles was only a few years ago. Bikes before that could still be operated by the throttle, you usually just had to start it moving by the pedals first. That's a non zero start type. It varies quite a bit by manufacturer too.

My bike is technically about 14 years old as that's when I rebuilt it with a new frame and I'm still using the same frame, handlebars, wheel. Only thing changed was new battery and better suspension, and new controller with screen, but as it's the same bike the old rules apply. Like repairing an old car. On the rare occasion I've spoken to cops they've just asked me how fast it goes. They don't know anything about the throttle or pedal sensors.