Exchange of Realities

It gets people killed in horror movies, has led to more misunderstandings (or cases of people knowing things they probably shouldn’t have) than almost any other plot device, often results in the person with the right skill being in the wrong place when needed, and can slow a plot to a crawl. And that isn’t even taking into account the frustration that can come from the GM multitasking, or from figuring out how to keep the rest of the group from either getting bored or knowing exactly what’s going on when their characters should have no clue. But despite that, you often hear someone cheerfully suggest, “Let’s split up, gang!”, the people around them follow through, and the GM agrees to this. Why?

1. Avoiding arguments. If the group wants to split up, who are we to railroad them into staying back together? It’s their own fault if part of the group blunders into a fight that was designed for the whole group.
2. Avoiding boredom or frustration. For the GM who can run two scenes at once (probably due to running by play-by-post or chat), it’s a way to run two varieties of scene at once—and have a scene of the kind we want to write keeping us from being completely bogged down by the scene we’d just as soon get over with. (Note: there are very few GMs who will actually admit this.)
3. Scheduling. Whether it’s a freelancing job or an unavoidable field trip, time zone havoc or unavoidable technical difficulties, one character’s player (or multiples, sometimes) just can’t make it at the normal time. What to do? Let’s send him over here for a while with this NPC and they can meet up at the end. It gets them off screen, but they aren’t sitting around doing nothing, and what they are doing can be figured out at a different time and might be useful later.
4. Connections between characters. You ever seen one of those times when two characters who ordinarily can’t get along to save their lives are isolated from the rest of their companions and have only each other to depend on? (Note that this does not always work; some people will just keep bickering anyway.)
5. Use of characters who just don’t work for the purpose of the scene with the full group. Sometimes, you just can’t get two characters in the same scene without something going wrong. There are two people who aren’t aware of what one of the NPCs really is, and today’s the wrong day for them to find out. The person the group’s trying to get some information from clams up around all of them, but one might be able to talk her into opening up. One player just plain can’t stand a certain NPC, and nobody feels like dealing with the inevitable clash, but there’s something that NPC is needed for.
6. Information. While keeping secrets is the most obvious reason to split the party, a split party is a good excuse to disseminate information as well. Maybe you’re giving each portion of the split group one fact and seeing if they can put it together. Or you’re going for a more Rashomon-style scenario, telling each about the same thing but from different perspectives. Or there’s just plain something you only want a subset of the group to know. Sure, you could do it in sidechat, but this keeps you from accidentally ending up in a paradox, and if you want people to know that something’s up, this is the best way to arrange it.
7. Uncomplicating a scene. Unlike “Avoiding boredom”, which only works for a known multitasker, this works better when you run your split scenes sequentially rather than simultaneously. One scene with ten people is hard. Two with five each can be a lot easier. This happens a lot with fights, but is also likely when dealing with very large parties.
8. Divide and conquer. What list of splitting strategies would be complete without this one? Dividing the group up breaks some of the synergies it might depend on, weakening it by more than would be expected from simple division. It can allow a group of opponents to use tricks targeted to each without worrying as much about one member of the group compensating for another’s weaknesses. If you’ve got a social monster in the wings, or a shapeshifter with duplication capabilities, they might even be able to subvert or replace one of the stray group members. A lot can go long when people aren’t there to look out for each other, can’t it?

Yes, splitting up the group requires more attention, special tactics, and a lot more patience. But that’s a reasonable price to pay for all the advantages. So let them split up, gang—particularly if you have some say in who’s with whom.