Reining in my players?

Any DMs have suggestions about how to keep your players from running all over the place and accidentally dividing the party? In general I have a really good group of players, but a couple of them have a habit in dungeon crawls to decide to see what's around the next corner while the rest of the party is discussing what to do next. In person this is easy to reign in because they can't go anywhere that I don't describe or draw out for them. In Roll20 they can go anywhere dynamic lighting walls allow them to. I've tried hitting the loner with an ambush or something similar but so far that hasn't deterred them from the reckless behavior. Short of going to the older "fog of war" function, I'm not sure what else to do to keep the party together.

The only place to discuss problematic behavior is in-person out-of play. But if one or more players can't help themselves but to peek around with their tokens you have basically three options: - use standard fog of war - use one way windows to contain the tokens - kick the player out of the game (not an option you want to use with ADD/ADHD friends). As gamemaster of many groups, some fixed long campaign groups and some oneshots,  standard fog of war is the preference. My reasonings are: - requires less preparation. The fun in RPG is about the play, not about the preparation - prevents spoilers. Did you know that a token with 120 feet darkvision on the right spot in  Arauthator’s Lair (Rise of Tiamat) already can see the end battle near the entry? - gives peace of mind to wandering players that can't help themselves.

Instead of using a hamfisted OOC method to reign in PCs that foolishly separate themselves from the protection of the group, making your ambushes even more dangerous or utilizing more traps is a good way to award lone wolves with their just desserts.  Keeping the group together really isn't the GMs responsibility and a lack of common sense tactics on the part of the players is a detriment to themselves and by extension the rest of the party. No one will keep them in line better than their peers in the party who decide after having seen this happen enough, to gang up on an errant partymate, each wielding a sockfull of silver pieces to drive their point home. A GM that micromanages the PCs decisions is missing the point of their responsibility as game master. By taking away their freedom of choice, you run the risk of railroading your players and there is little that demoralizes your players more than the feeling that they really have no choice, and they are left with the feeling that they can do little else but sit back and watch you play the game for them.  The old addage of ICA=ICC (In Character Actions=In Character Consequences) rules the spirit of most RPGs and it's a big part of the fun of exploration. So in the same breath, while I did say that punishing a PC for silly tactics is most often warranted, I'll also recommend to occasionally award your players with rampant wanderlust with the odd discovery of something once in a while. Players come in all shades and flavors, and explorers are the ones that really enjoy finding out what is around that corner, or over the next rise.  

Even Fog of War doesn't really solve this. I don't think it is solveable: Players don't always think tactically, and ultimately, they're playing to have fun and everyone's definition of that is different. Some want to move cautiously, others want to explore "right now", and some really don't want to be the ones close to an encounter and will lag behind the party if they can. But you can modify player behavior some. I play 5E with Fog of War rather than Dynamic Lighting, in part to give me more control over presentation, and two of my players just love to play "rearguard" so much (avoiding the fight) that they can either/both become separated. And one is playing an impulsive character who tends to run ahead when the others are debating what to do. (good RP, terrible tactics). While I could stop that by not revealing, my view is that I'm not there to tell him 'no', I'm there to referee the results of his decisions, good or bad. I try to never take away the decision-making from the player, that's a big part of the fun of a D&D game. I have used the ramped-up-encounter bit.  Once I designed a falling wall trap, which cut the lagging player (just one) off from the party.  He got to listen while they had fun with a puzzle in the next room (it took them a while, and one encounter, to find the release for the wall).  While he did, he wandered into a room full of zombies (an encounter designed for the full party) and ended up running out of the dungeon.  I didn't really count that a success, but it did underscore why splitting the party was bad. But my real solution came after reading Keith Amman's Live to Tell The Tale party tactics book.  I boiled that down to a small set of handouts stressing how PCs could work together tactically to augment their abilities (eg, PC A knocks an enemy prone, PC B with the big sword gets Advantage on their turn).  After a few games introducing these, along with some suggestions to each player on how they could best apply their abilities in concert with the others to deal more damage more quickly (something near and dear to most players), things did improve. They thought about encounters more, made better uses of their abilities, and sometimes even managed combo moves (I also had to ramp up encounter difficulty to match them). And to do that, they had to stick together better, and function more as a cooperative team. I've still got players who lag at times, and the other who periodically runs ahead and triggers ambushes all by himself. You can't really change how someone fundamentally wants to play their PC.  But you can tone it down some, if you can get them to really think about alternatives.

There's always that one player that always ignores the old adage "Never Split the Party!". You mentioned that you've tried having then encounter ambush's and such: keep that up! Pit or falling wall/portcullis traps: they don't have to be lethal, just hard to spot and deep enough to trap the errant PC and make them twiddle their thumbs until the others find a way to pull them out AGAIN .  Ambush by something with the ability to charm, dominate, or otherwise turn the PC against the rest of the party. Also  Doppelgangers or similar monsters. The player's constant forging ahead makes the rest of the party rush to keep up, causing them to miss things, like the baddies hiding behind the tapestry, a secret door, or a faint symbol scratched on a wall that they would have spotted if they were moving slower. (The players will of course find these things later, when it's too late) The idea is to show that separating from the party is not only dangerous for that PC, but the rest of the party as well. In this way you recruit the rest of the players to help you rein in the prodigal.

In coordination with many of the above suggestions-approaches,  I'd also recommend asking, looking, thinking about the underlying reasons, motives, drives, for that behavior? I suspect this might be Player 5's way of telling Players 1-2-3 to hurry up, they want to get on to the next room. That is why they are not deterred by an ambush. They would prefer to play an Ambush than whatever players 1-2-3 was doing (searching, counting loot, RP'ing, whatever it was).

Usually I'm not as nice as many of the other GMs posting here. First occurence = trap, ambush, monster. Second occurence = almost the same, but deadly.