Yes it has come up. With dopplegangers as I was describing those few dead ones in their natural state. I described them as completely hairless.
That's not what I meant.. What I mean is, did
ankything turn on the fact that doppelgangers have no body hair? The mere fact that you stated it, because you read it from the Monstrous Compendium entry, isn't an instance of it actually mattering at the table.
As I said, in over 30 years of GMing I have had things turn on hair colour, skin colour, and size of feet (for fitting magic footwear) and head (for stealing an NPC's helmet). But never on whether or not a doppelganger (or anyone else, for that matter) had hair on its arms and legs.
That's how dopplegangers act which makes that tactic distinctive to them. If you encounter shape changers that act differently, you can use that as a clue to rule out dopplegangers.
Nonsense. Wererats follow people to inns all the time. I'm prety sure I've seen modules with werewolves in inns. Following people to inns is not the least bit a unique doppelganger trait. That's part of my basis for saying that, even as GMing advice, it is utterly banal - and as "lore" is just rubbish.
Not knowing it means that I have to ignore it or come up with it on my own. In that case the game is doing nothing and is at a lesser depth than if it offered that information.
How does that information add depth? You seem to be equating
depth with
detail. My point is that that is a highly contestable equation. It doesn't hold true in any other representational art form, so why would it hold true in RPGing?
Here. To help you understand why the lore about dopplegangers following victims to locations is lore, I'm going to use real world example.
Bonobo chimps like to kiss and have sex. They do so to resolve conflicts, rather than fight. That's Bonobo lore. According to you, if I were to include that lore in a D&D write up on Bonobo chimps, it would cease to be lore and somehow become a suggestion that DMs use it.
The reality is that it would remain lore and not be a suggestion at all.
There are so many differences between a zoolgical treatise and a Monster Manual that it's hard to know where to start.
But here are two.
(1) The goal of a zoolgical text is to inform about a real state of affairs. The goal of a Monster Manual is to provide RPGers with material to run their games.
(2) The creatuers in a Monster Manual are governed by fictional logic. Eg shapeshifters take on the form of innocent people and wreak havoc. The "lore" in a Monster Manual is meant to help identify and elaborate what is distinctive about them from a narrative point of view.