Dead Man's Switch

Today I discovered why last year's long puzzle to do with the Grim Reaper deleted itself after I got to the end of it, and its because it activated something like a Dead Man's Switch, since the answer to the final riddle was a grave, and that's why!

I know from the Cicada 3301 puzzles that they were working on something similar, so it doesn't surprise me. Instead I'm impressed how far they go to make these things possible!