I know these threads about kill switches usually go south but I’ve just heard of this and it sounds good. There are people who’ve used them and seem to like it. They thought of several things, you can connect multiple wireless fobs to it for either captain, cuts power, or passenger and it just alerts. Also allows restarts shortly after killing the engine so other can pilot the boat if captain goes over.
https://buy.fellmarine.com/mob-xtag.html