/snip
I can imagine the outrage if it were suggested that players be required to defend their preferences in making characters they want to play!
RC
But, players are required to defend their preferences all the time. After all, what is a player background if not a defense of their preferences? If a player wants to play X, he has to run it past the DM before taking it every single time. A player who comes to the table with a character created without the DM's knowledge could quickly find himself rolling up a new character as the DM decides that the PC is too overpowered (or underpowered, or doesn't fit with the campaign etc.)
In what way is a player not required to defend their preferences?
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I look at this like this. I hate elves. I've hated elves for a long, long time. I hate elves because every elf I've seen played, or nearly so, has been a human that can see in the dark. There's never any schtick that defines the character as an elf. Dwarf? Halfing? Dragonborn? Sure, I see those players bringing stuff to the table all the time that defines that character as a member of that race. They make that character easily identifiable as a member of a particular race.
Elves? I have almost never seen it.
But, and here's the but. I don't ban elves from my table. Why? Because I know that there are people out there that can do justice to an elf character. Who am I to tell the players that their character just doesn't measure up to my standards? I am nowhere near that arrogant. Well, maybe I'm close, but, still.
To me, when a DM says, "There's no X, because I just don't like X" that raises HUGE red flags. For one, what else doesn't he or she like that hasn't come up yet but might affect what's going on down the road? For another, where does it stop? After all, "I don't like elves, so you can't play an elf" isn't so far from "I don't like your character doing X, you can't do X".
Not that that will necessarily be true. It very well might not be true. The DM could be a fantastic DM with this one small hangup. But, that worry is going to pop up in my head because every single poor DM I've played with started with the line "I don't have X in my game because I don't like it".
Not that banning X makes you a poor DM. Let's nip that little misread in the bud right here. DM's most certainly can ban whatever they like. But, when a DM stands up in the Big Daddy Chair and rules from on high, I'm going to be much more reluctant to sit at that table.