Running a home Pathfinder game and running a Pathfinder Society game are two completely different things. In a home game, the GM can control what rules items are legal and can become intimately familiar with the options that his characters are using. This means that the GM only needs to know the rules for the characters and the particular NPCs that are involved with the current session. For most sessions, this is all you need, and therefore a prepared home game GM can appear to be the stereotypical all-knowing rules arbiter with a sufficient amount of preparedness. This is impossible in Pathfinder Society. There are currently 34 Campaign Setting books, 38 Player Companions, and 12 hardcover books with material legal in them for Pathfinder Society. While a lot of the books only have a couple of items legal in them, there is still a lot of material available out there – it’s impossible to know it all. And that’s not even counting the massive amount of crunch that’s coming out in the Advanced Class Guide this August. The 6 players at your table could be using any of that crunch for their characters, and they could be using completely different crunch than the 6 players from the last time you GM’d. Some GMs are better at knowing fringe material than others, but nobody’s perfect. No matter who you are, there will be some PFS game where a player pulls out some random build that you’ve never seen before.

The point is, as a PFS GM, the perception of omniscience is overrated because someone will play something that breaks it eventually. It is okay to admit “I don’t know.” In fact, you should admit it every single time you don’t know something. Taking this approach will have a couple good effects on your games.

The first effect this will have is help players build trust in you. At some point you’ll be running an encounter where the “rules are broken.” Examples of this include two identical-looking monsters trying to pretend to be one, or a humanoid enemy who isn’t flanking getting sneak attack, or anything else that appears to break the rules until you see the stat blocks behind the screen. At this point, you can’t tell the PCs what’s going on because that would ruin the encounter. Instead, all you can say is “You’re right, when two people are positioned like that it’s not flanking and therefore you don’t get sneak attack. Isn’t it weird that he’s getting sneak attack still?” The more trust your players have built in you as a GM, the smoother this interaction will go, and the more fun everyone will have as a result.

Flanking? I don’t need no stinkin’ flanking!

The second effect this will have is it will allow you to learn new things about the rules. This is especially true for newer GMs, who may not have the years of experience that some of us have with the system. I know that when I first started GMing, I had a lot of trouble with how the grapple rules worked and basically avoided that section of the rules. As my luck would have it, one of the regulars started playing a character whose main focus was grappling. It only take a couple games running for a grapple PC to really understand how grapple works. Now I have a grapple PC of my own, you might know her as Venture Captain Komana Higgenstrom. Reading the rules will certainly help you learn them, but actually using them in play will reinforce them stronger in your mind. You just have to admit that they aren’t in there as strong as you would like.

The third effect this will have stems off a huge difference between running a home game and running Pathfinder Society. As a PFS GM, you are not always the GM. I am certainly a prolific GM – at time of writing I have 203 tables of credit. However, I have 150 tables of playing to go along with those 203 tables of GMing. Almost everyone who GMs for Pathfinder Society also plays in the same campaign. As a GM, your style of GMing will certainly influence the players at your table, and there’s a chance that one of them may be GMing for you in the future. What happens when that one person thinks that to be a good GM you need to have an amazing grasp on the rules and then makes tons of mistakes at the table he runs for you while not admitting that anything was wrong? Would you like it? If no, then why are you subjecting other people to the same attitude?

Core Rulebook, shown actual size.

The most important effect this will have on the game is that it helps set the tone for the game. The players are smart. They know when you don’t know something, especially when it involves their character. When you try to force an incorrect ruling on the table, you’re sending a message that you are going to be an antagonistic GM. This is not an attitude that you want to be putting forth. You are there to tell a story with the players, possibly to give them a bit of a challenge, but most importantly you are there to help everyone have a good time. Appearing to be antagonistic is not conducive to that task.

Now, you may be wondering why I’m suddenly talking about this issue. I want to be perfectly clear that I’m not talking about this because I’m seeing a lot of people in Philly acting like they know everything. But when I started to brainstorm ideas for GMing advice, this shot up to the top of my list and was just begging for me to write about it. Sometimes, the prolific GMs sound like they know everything. We have some really good GMs in the city who know a lot of the system and discuss lots of corner cases and unusual, high-powered character builds. We don’t know everything, but admitting that we don’t know everything has allowed us to get to where we are. So, if you’re worried about GMing because you don’t have a perfect grasp on the rules system, that’s okay. Nobody does. Nobody is omniscient.