Worst possible outcome is blarg has a power role that helps town, or he's bulletproof or something, and we end up losing it by lynching him.
You could apply this reasoning to literally any lynch at all. This is role madness, not role mild irritation, after all.
Or that Blarg is protected from lynch and monkey is in on that, so the Blarg bus costs us even more. That's not even considering the possible power roles that could actually have if lying.
If Blarg is lynchproof scum, the game is unwinnable if town loses whatever killing roles it has, you realize.