In the special case of Geographers, it's really a though call. It's common sense that if a Geo is getting healed it's because it's been hit. But it's a somewhat "passive" monster because it's usually ranged class that rape XP from 'em. And it's not aggro at all. I mean, it cannot even move, it can't aggro you at all unless your dead next to it. It's really though to make it look like you're in danger from it (the whole point of aggroing in my book).
I can't see myself punishing someone for not knowing it was hit before. Come on, let's picture this : I come with my mage in a screen where another is FB a Geo. Fine, there are 2 of 'em, I shall hit the one the Mage is not hitting. That is considering I'm a jerk because I know what the other mage is doing!
But still. It's really a though call. The only thing I might see as KS in this extra special case (Immobile non passive, non ranged monsters) is if it's repetitive.
Otherwise, use common sense and patience.