No one agrees on whether or not a dead body will unlock a smartphone

From fingerprints, to facescans, to possibly even sweat analysis, biometrics have become the default way many of us secure our data and unlock our smart devices. But with that ubiquity also comes risk, as security researchers have demonstrated time and time again that many of these supposed safeguards are susceptible to multiple-step hacks. 
But what about, you know, single step hacks? Like, for example, hacking off someone's thumb? The question of whether or not a dead body or missing limb