Nifft said:
In many games: yes. Evil races are evil for a reason... and that's the reason. So you can kill lots of them every session and never lose sleep. They exist to die at the end of a hero's sword.
Yes,
But Goblins are not an Evil Race.
They are a "Usually Neutral Evil" Race.
That means that "More than 50%" of Goblins are Evil.
That means a lot on Non-Evil Goblins are running around. Even if 85-90% are Evil of some sort, that would still leave tens of thousands (if not more) of non-evil goblins running around (based on how many of the vermin-like creatures are running around).
If it doesn't have an Always in the Alignment Block, there is no guarantee that a given Creature is Evil. Or Good. Or Lawful.
But, I don't think Miko will Fall. Here's why:
The Lawful Stupid Paladin Archtype has a lot of Fuel in the Tank. Miko's been offstage a lot. The Paladin as "Holier than Thou" and "I'm Always Right" "Smite now, Detect Later" has reams of material to keep Rich Busy.
Unless he really has a bunch of material related to BlackGuards, Fallen Paladins, or Maybe a guest Sabine-Miko "
Peaceful Contact with an Evil Outsider" Drawn by
Boris Vallejo & Julie Bell 
(Not all clicks grandma friendly); I don't see why he'd rush the "Miko Goes Coo-Coo" Angle.
And I think that is waht it really boils down too:
Does Rich want to continue to use Miko as Paladin Material or as Blackguard Material?
Or maybe just "NPC who Advances Plot".