Sure, you can hack Fate, but should you? Sometimes the answer is yes. If you’re playing a supers game, you’ll need to add some super powers. If you’re playing a game about street racing, it might be good to have a few rules regarding vehicles.
Sometimes you don’t need a new rule, though. Sometimes all you need is a ruling.
A ruling is a decision that your playgroup makes—usually guided by the GM—about how something works in your game. Rulings cover special cases that aren’t explicitly covered by the rules of the game, cases that require some interpretation. A new rule, on the other hand, is a change to one or more of the sub-systems within the game, or the addition of a new one. Where a ruling is an interpretation of how the game works, a new rule is a change to how the game works.
For example, when you tell a player that his character can’t take that long- range sniper shot because the boat he’s on is bobbing up and down too much, you’re making a ruling. When you explicitly state that no one can make long- range sniper shots from a boat, you’re adding a rule. See the difference? One affects the current situation and may have ramifications later on, the other affects all such situations.
So when do you use one or the other? Use a new rule if you’re addressing something that comes up a lot. Whether you’re finding something problematic or you want to be able to do something new, if it happens a lot, it’s often a good case for a rule. Use a ruling if you’re not sure a situation will come up again, or if you think it’ll be rare.
If you make a new rule for every situation, you’ll wind up with so many rules that you can’t keep track of them all. If you make rulings for the edge cases, on the other hand, you’re freer to change them later. Sure, you can change a rule later, but some players will call foul on this—and rightly so! Worse, you make your rules even harder to remember and keep track of, especially if you’re changing them all the time.
Here’s the secret—rulings can become rules. If you make a ruling about sniper shots on boats, and you find that situation comes up again and again, turn it into a rule. If you’ve made a ruling multiple times, your players will probably remember it, so there’s less chance of a rule that just gets forgotten.