I still disagree. If I'm the survivor, I claim D1 immediately, and broker a deal with town and scum. Why?
1) I win no matter who wins, so long as I don't die. That's all I care about. Not town, not scum, just surviving to win.
2) I have an NK. That means I can affect the game at night at any point that I'm still alive, including killing claimed PRs, etc. if I want.
3) I have a vote. That means I can affect who gets lynched during the day.
Why do those things matter? It's in the best interest of town that I NOT use my NK, since I'm most likely going to hit town (see town vigs in almost every game). It's also in the best interest of town that I NOT vote, since anti-town voters help mislynch more often, especially since I don't have partners to bus. That means that with 14 alive, it takes 8 to lynch, but without my vote, scum needs 50% of town or more to mislynch (8 votes out of 13 players, 10 of whom are town means if ALL 3 scum vote for one town player, you still need 5 town votes).
So then, why won't scum NK me? Because I inflate their team for the endgame. As mentioned, I basically count as a 4th member, and give town one less mislynch for the game. 3 scum, 3 town is a scum win (generally, not taking into account JK and such). With survivor, scum with with 4 town alive.
The greatest risk is a spiteful town lynching survivor anyway.