xyzzy's recent PGO3 Marathon game got me thinking about trying to create a 3p setup in which scum had an incentive to play notably differently from town, ideally with associative tells. This setup has a 50% EV (not hard to achieve in a 3p), but also creates play patterns for scum which are quite different from those for town; if they want to lynch the unhammerable player, they have to be the first vote on their wagon (whereas normally it's best for both scum and town to wait before voting), so they have an incentive to push on the other player instead. The consequence is a 3p setup that actually has an informed minority and may allow the normal scumhunting tools to be usable.
The setup should be immune to breaking strategies because although you can try to force a particular player to hammer, doing so will end the game regardless, so there's no way to gain information that influences your own future play.
Well, lynches are town-directed, so under EV assumptions scum don't have any input into how they happen.
In practice, scum have much more opportunity in this setup than in SS3 to aim for their win condition, but town therefore have much more ability to catch them doing so.