No security is perfect , not even a dead man ' s switch . If they can break the ability to prevent it , it ' s worthless . And if it can ' t be prevented , it isn ' t a dead man ' s switch , it ' s just a tuned release . Given enough time and effort , any code requiring a human being can be broken . <| sep |> The rule used to be as far as I can tell , as soon as there were more than one legendary permanent with the same name on the battlefield all of them die . The current rule is that as soon as a single player controls more than one legendary permanent with the same name , they choose one of them and all the other ones die . Technically speaking , none of that is officially sacrificing if there are effects that care about whenever you sacrifice .