I am assuming by kill switch you mean on the throttle..as I can't think of any other time you'd want to shut down your aircraft while operating..
On a glow engine throttle cut is a function of trim..you program a computer radio so that when you a throw a switch to run, you have cracked the carb open to idle....on shut down you when you throw the switch you close the carb completly...the engine shuts down..you do the same thing on a non computer radio with throtle trim manually..
On a gas engine there is also a switch to kill ignition..
Hope I understood your question correctly