[KenWittlief]

we built one with a 6 foot cable in a box that is separate from the OI.

That way you can have one person hold the disable box, so they can hit the kill switch when needed, instead of the driver.

The driver always thinks they 'have it', until they run someone over.

Much easier to have a second person on the kill switch, who knows, when the robot crosses this line, shut her down!