If there is a single lesson I've learned in all my years playing Mafia is that players don't know dick about balance.
1. You can only establish balance after knowing ALL the roles in the game.
2. There is nothing saying the game can't, in fact, be balanced.
In situations like this, where there is some anti-utility role, scum is usually smart enough to realize that they have to be on that lynch otherwise they look scummy by comparison.
Consider just last game with oro as Turn Coat. Scum would have preferred oro stay alive so they can convert him, but being conspicuously not on his lynch would have been suspicious, so they pushed for his lynch to look town sided.
This is also the exact same scenario. It is a better guarantee that scum is on Grey's wagon than it is that Grey is scum himself.