I think this would help a lot of people. There could be many ways to implement this, i personally thought of a last man standing starting automatically every month, people can opt in and they get auto kicked out when they reset the timer. They would also get kicked out if they dont log in in 10 days or 2 weeks or something. A mesaage announcing registration for the next Last man standing could be issued in the app 3 days before the beginning.
Alternatively, you could make only 4 last man standing per year, spring summer autumn winter.
Everything would be automatic, no moderator to handle anything.