Enphetamy it does, their scouts see the army wandering in the fog and can see who those troops represent, probably see their banners, they have the extra good vision you know.
I think elves would argue they want to keep the knowledge as is, or would want compensation for the loss like increased odds of enemies being lost (maybe it's thicker fog that the elves can't see through to know the kingdom the troops fight for, and the thicker fog makes troops even more prone to getting lost than the old one).
But there's a counter to that data, the attacker can just Gate troops back, making that info about lost troops bad info. Maybe that's enough counter balance?
