One of the things I've come across when playing in established settings is "knowledge level of the setting". And you don't have to be playing something published specifically for RPGs.
- Stargate (everything)
- Farscape
- Underworld
- Star Wars
- Star Trek (any series)
- Alias
- James Bond
- Firefly/Serenity
and RPGs
- Forgotten Realms
- Greyhawk
- Traveller/3I (any edition/version)
- Kingdoms of Kalamar
- Dragonlance
The problem is, fans of the novels/setting will be heavily steeped in the time-line, events, culture, clothing, characters etc. They will be scouring interviews, short stories obscure and not, etc. for more info.
I call them 'setting lawyers'.
At cons for running MGT I run a home-brewed adaptation of the movie/series "Firefly/Serenity". I tell the players that this is MY version, MY interpretation. I know there are differences between what I have and the series/movie but this is how I see it. Please no trying to contradict me to match the show.
Then I still have the player who wants to debate me for 30 minutes on where the hatches are, which ones are airlocks, and how the ship (a firefly) would dock to a space station or another ship.
OR
Correcting me on how clothing is worn, how they would speak, etc.
Yes the do know quite a bit (in some cases just convinced they know quite a bit) but all they are really doing is an exercise in showing off what they know/think they know while slowing down the game. I've actually had other players finally say "Hey, alright? The GM said this is how it works then this is how it works can we get on playing already?".
It's really just loyalty to something they love and what they think they know about it. It's really great but half the time there is misinformation and assumption and what they heard 'from friend who learned from some other friend from some guy that the prop master on the set said" (ok, not quite that silly but close).
Again with me I'll admit (for the 300th time) why I am anal about keeping straight where sources fit inside that setting. Are they recognized by those who 'keep the canon' as official? (not every SW novel is 'canon' only a few are). If not then it's "How well does the writer know the setting?" and so on.
Bring on the setting lawyers. I have a crab mallet from back in Delaware I haven't used as an attention getter for a while *playful smile*