ExploderWizard
Hero
There's a couple of points there though. A player who narrates a small bit of your setting isn't touching the massive amounts of stuff you have to play with. OTOH, the character is generally the only thing the player has to control, so, messing with someone's character becomes a lot more difficult.
Its just the theory I was illustrating. Scale is another matter entirely. In a game where characters reach level 30 is making one decision for a character at level 2 really that big a deal compared to all the time they have to control the character?
Secondly, I've rarely seen any campaign that didn't allow players to narrate their backgrounds to a large extent. How is that not stepping on the DM's toes? Sure, the DM can veto, ammend or whatnot background ideas, but, by and large, players can determine their own backgrounds within the DM's setting, to the point of adding NPC's (family, lords, mentors), locations (home, hideout, whatnot) and even setting elements (religious orders, wizard schools, etc.). So, it's not exactly out of left field for the player to have some input into the setting during the game.
No arguments here. A DM who asks for backgrounds and such things is openly inviting setting creation participation just as a player who happily goes along with a railroad is consenting to a form of limited DM contol. No badwrongfun is taking place if the group is cool with these arrangements.

It also depends on what system you're playing. FATE allows the DM to specifically trigger elements of a character. If a character has a particular attribute, the GM can pretty much force the player to play that trait, or heavily penalize him if he chooses to ignore his trait. Other systems can do all sorts of things. Heck, even traditional D&D lets me as the DM, charm or otherwise magically influence characters.
How many times have DM's turned to players and said, "Umm, you want to slit the innkeeper's throat and steal the cash... what alignment is your paladin again?"![]()
Not familliar with FATE at all but I do have experience with such concepts. In GURPS you can choose to ignore inconvenient effects of disadvantages but if you took points for them then expect your earned points for roleplaying to dwindle to a trickle. In this case it isn't the GM controlling you, it is you choosing to ignore limitations that you imposed upon yourself during character creation usually for the purpose of getting other benefits.
As far as the paladin restrictions go, I wouldn't tell the player he/she couldn't do certain things that the character was situationally actually capable of doing but the would be consequences including no longer being a paladin for starters.