Then why do we have moderators? To enforce the rules, yes, but also to use their judgement in specific cases. It's not a horrible thing to do. Yes, do that. Why would we even need court cases in real life if everything could be determined by a rule?
The rule could just say "GM can use their own judgement if they believe the players are unnecessarily extending the game" or something similar.
But... the thing here is that mafia GMs pretty much do their own thing. Add it if you like--to your own games. It might catch on.
Sunflower: Stealth lynching can happen. Some people just don't pay much attention, and not everyone is lenient. I'm not really going to argue about the game that I'm not in, but.