So because a player is new we can assume that they don't know anything about anything? Does that automatically make them exempt from being able to use scum tactics? I trust new players more than not at all.
Well in my experience (and I've been right every time) this has happened in quite a few games, and It's always the same thing. The person is inexperienced and sounds scummy because they don't realize what sounding scummy is. An example is in my first game, where Beary wouldn't trust people who were obviously town, and ended up trusting the last two Mafia players. She trusted them because she was inexperienced. Either way, her claim was extremely believable.