I think most current ESCs are designed not to turn the motor on if the plane is inadvertently powered up with the throttle not at idle, in fact, that's how you enter the programing mode on some of them. Most ESC's just plug in to the reciever as if it were a throttle servo. Futaba servos will work in JR recievers if you cut off that little tab with an Exacto knife. You may also have to bevel one side of the plug. Since the positive (hot) wire is in the center on both JR and Futaba, the only thing that happens when you plug in backwards is the signal and ground wires are reversed and the servo doesn't work.
BTW, the positive and the ground plugs on the reciever are just common busses. You can plug your battery into any unused channel and power the reciever. That's why a battery eliminator ESC does not have a separate "battery" lead coming out of it. It just powers the reciever through the throttle channel.