I doubt it's a switch. There has to be some data transmission between the charger and the car, especially on Tesla's, to throttle the power, and to tell the car if it's getting AC or DC. Superchargers, in particular bypass the cars on board rectifiers and feed DC directly, and the current is managed by data coms with the car.
I'd bet money that the "we're plugged in don't move" functionality is software triggered by the data connection with the charger. Probably with a back up sensor reading if the charge port door is open.