Well, normally in an event, there is an indicator that tells you who is what.
(Last Year, Zurg had a "Psychic" post style. That way, if I was a Zurg, you'd know, even though I was completely covered.)
Not to mention there'd be an attack button underneath. (People on the same side don't have an attack button.)
I'd expect Gaians would have normal posts, Vampires would have Gothic looking/Bloody speech bubbles, and Werewolves (Because there will be werewolves) would have erattic/scratchy speech bubbles.