Tom Cashel said:
Try telling my players that. They know that the rulebook is always right.
I hope this comes across as helpful, and not as a trollish snarl:
In some ways, I treat the job of DMing the same way I treated the job of being a basketball referee. I learned the rules, and I studied the rules, even the obscure ones, and I carried that knowledge into games. It has been said that there are three attitudes a referee can have:
1.) I call them as they are. ("I never make mistakes. Do not question my authority.")
2.) I call them as I see them. ("I'm doing my best; I'm only human, but I may make mistakes.")
3.) They ain't nothing until I call them. ("I am the living extension of the rulebook on the court.")
I personally think #1 is the wrong attitude to have (all of us make mistakes and players tend to chafe at a DM who never admits mistakes). I also think #2 leaves you open to being run over by the players (RPG players will whine and complain for "calls" as badly as any NBA player). That leaves #3 - and I think it's the best attitude to have for reasons I will make clear in a moment.
"Rule #1 when I DM: The rulebooks do not enter the gaming room. Only the players do."
Corollary 1: Players may not resort to an "appeal to the rulebook," nor may they "quote the rules" once a decision has been handed down. For the purposes of decisions made during a session, I, as the DM, am in fact the rulebook. There is no higher authority. Rules are my job during sessions, not the books'. The books' job is to teach me the rules I don't know (or don't know well) between sessions. That makes the rulebooks the DMs' learning tool, not the players' weapon.
Corollary 2: If a player feels a ruling was unjust and/or incorrect, he may consult with the DM in private, after the fact, and make his case. Also, if the DM makes a judgement call where he is unsure of the rule in question, he may choose to review his own decision. The DM will spend the time between sessions researching the rule in question (a quick drop by the ENWorld boards is usually enough). If the DM finds out he was mistaken, he will announce his judgement error at the next session - but the "correct" judgement will NOT be retroactively applied. Rather, it will be applied to all judgements going forward. The same applies for house rules; they are never applied retroactively.
I have found that this rule and its two corollaries tend to take a lot of the "players vs. the DM" conflict out of the game. The DM - not the players - is cast as the definitive source for "on-the-fly" interpretation and enforcing of the rules. The DM is cast as fallible, but just like any sports official, his initial calls are not overturned (we don't do "instant replay challenges here") - only corrected going forward (when was the last time you saw an NBA official reverse a foul call after he had made it or saw a Major League Baseball Umpire say, "you know what, you're right - that was really a ball... hey, scorekeeper, change that strike to a ball!")
You tell the players that you are in charge at the gaming table and you are the ultimate authority. And by taking away the rulebooks from the players at the table, you reinforce that authority. In a sporting event, you don't see the coaches or players whip out a rulebook and shove it in the referee's face. Why should RPGs be any different?
Hope that gives some useful advice... seriously, I think that it's the best way to cast yourself as, "the living voice of the rules," while leaving yourself room to make mistakes. And most players will get the sports analogy that calls don't get reversed, but the rule may be interpreted differently in the future if the referee studies the rulebook and finds out he was wrong.
--The Sigil