I literally played so many games where it was worded like:
The Morbfia factional kill is mandatory. If no factional kill is submitted by the final hour of the Night, the kill will be determined randomly from among living members of the town.
Mafia members will talk through a Forum PM and can perform faction kills/ It is not mandatory to do night kills or other actions.
The Bandits have a mandatory Factional Kill (if not performed the kill will be randomized among living town players)
But never quite like