The other half of this hydra is Kunkstar7. Do you guys wish for us to identify which one of the heads is posting, or does is not matter to you?
As for MMM's questions...
Almost always against it, except when it comes to VIs. Scum never kill those, and they are detrimental to the game, so it is usually good for town to lynch them ASAP, unless there is a vig.
It's not really that helpful (usually), but I wouldn't call it scummy.
I say lynch all liars that are caught. There may be circumstances where town could benefit from a townsperson lying, but these are rare, and I can only think of one at the moment (Paranoid Gun Owner claiming Doc to draw a Mafia NK). If you get caught, well you knew the risk of lying going in.
I have played both games multiple times over, but am not as familiar with the books.