In my opinion your friend is wrong. Mount the start/kill switch close to the engine where it can be reached and is visible while choking the engine and starting the engine. ( that way you allways know ignition on--ignition off.) will keep you from cutting your hand off or braking an arm. Also needs to be convenient so you can kill the engine if it starts backwards, or the prop slips.
If you want to kill the engine with the Tx. use the throttle down or cut off toggle/switch to close off the carb. NOT THE IGNITION SWITCH.
Just my opinion.