Flatus Maximus
First Post
And this is kind-of where I'm coming from. A ranger knows how to fight an elf. He knows how they are weak, and the exploitation of this knowledge is expressed in game terms as a +2 to hit. But if he doesn't know whether or not a given enemy is an elf, why would he get this bonus? He doesn't know whether there is an elven weakness there to exploit.
Further, there is no rule that states that he automatically identifies creatures, and there IS a rule stating he gets a bonus to monster knowledge checks against his favored enemies. This seems to suggest that he still needs to make these checks to identify the monsters.
This came up the other night at our table. The Ranger has FE aberrations (I think) and they were interacting with a shapechanger. We ruled that FE gives advantages to detecting and fighting, but not auto-ID, just as you suggest above.