Surely the bot should be designed so that all the activation valves and links are easily accessible? Poor design should never be an excuse for changing a rule. Allowing a tool to be used to reach into a machine would surely encourage people to make things even more difficult to deactivate? IE the valve is located right there, you gotta twist the tool around this specific path to reach it

I can probably count a half dozen times when I have been thankful that no activation of my robots has been hidden away under panels and difficult to get to in an emergency. If something goes wrong during a bench test I want the robot dead asap without having to make sure I have a specific tool beside me. It would only take one time to forget this for something to severely go wrong.