New to BW, Questions Vol. 1

Let It Ride
Nothing can protect players from a GM who doesn’t follow the rules, and that includes LiR. But LiR is supposed to prevent abuse. There are messy cases, of course, where you can argue either way, but you should never have players roll repeatedly until they fail, and they should throw dice at you if you make them.

Your example of Andy sneaking still rubs me the wrong way. If he succeeds at Stealthy, you Let it Ride. That means as long as he’s sneaking there, he succeeds. If he decides to assassinate or loot, you should not call for another Stealthy test. You’ve already established that he’s stealthy! What you can do is decide whether or not his original task and intent cover his new intent. This can also be done for focus. If it’s not central to anything go ahead and let him rob the vault or slaughter everyone like a ninja—but this is as much Say Yes as LiR. If you think there are new obstacles, they can’t be stealth obstacles, so you can call for a different roll. “Sure, you can sneak to the vault, but there’s simply no way to enter stealthily. There’s no cover. You’ll have to rush the guards and try to take them out (Knife or some other appropriate weapon) or do something else.” Or maybe “Sure, you’re in the vault. Stuff-Wise to get the good loot instead of the sacks full of useless old knick-knacks.” Different intent, different task, different skill roll.

If Andy fails, you’ve established that he’s not sneaky enough. It’s not enough for him to try to change his odds—that would be advantage and disadvantage, which he should have thought of for the initial roll. For LiR to stop there usually needs to be a change in intent and task—not sneaking into the same place or for the same reason. I’d let it go if he’s been doing other things, though. With a session or two in between, a different and clever plan, and some arranged advantage eventually it might be okay to try again. The trick here is that he shouldn’t need to—if it’s so important that it happen, don’t prevent his sneaking. Make the consequence of failure something that doesn’t block the plot. Maybe he manages to sneak as much as he wants and gets away but the guards get a clear look at him on his way out. He’s accomplished his goal but now he’s a wanted man! Or he gets away uncaught but takes that aforementioned arrow to the knee—and he can’t go to any physician because the guards will be looking for suspicious knee injuries. Those gives him the results he needs with an interesting complication.

Technically you’re always rolling Stealthy against Observation, but yes, I’m a huge fan of abstracting totally unimportant NPCs, especially in groups, as an Ob. I even do this with some plot-important, stat-unimportant NPCs, although that trick is a minority opinion here. Is it a hard place to sneak in? Ob 4. Really hard? Ob 5. Sneaking up on a peasant gathering? Ob 2. It’s simple.

Say No
If you tell players their characters just can’t do things because you don’t want them to, you’re doing a disservice as a GM regardless of the game. With BW you have the added concern that players often can (and should!) ask for huge results from one die roll. Sometimes the task is impossible and you say no, but sometimes it’s just too zoomed-out and you say no because you want them to break the intents and tasks down into more granular pieces. That’s perfectly fine, but maybe saying no is the wrong approach. You’re saying More Details instead, and that’s good, especially when Beliefs are on the line.

One roll to achieve your goals is boring. Ten rolls might be a session. A thousand rolls is an epic campaign. Match the level of requirement with the tone and scope of the goals/beliefs and the game!

Correct in how it counts, but you always apply it in the form of +1Ob to Character 1 due to the interaction with advancement. If you really need to handle it in a different way, remove Ob successes on the side of the person taking the penalty and then compare without modifiers.

Let it Ride is to protect against this GM here:
“Roll stealthy to get past the gatehouse, now roll stealthy to get into the front door, now roll stealthy to get down the hall.” The fact that it’s written in the rules allows the players to inform the GM that the game is being run incorrectly. I’ve had situations where there was a misunderstanding in terms of changed situation and my players called me on it. They were 100% right as well.

Wayfarer is totally on the money for Let it Ride when modifying a sneak type test from one intent to another.

Failure is interesting, it’s two things at once. It’s a failure of intent as well as a complication. If a player succeeds in a roll they get their intent, if a player fails in a roll they don’t get their intent (Page 31, last sentence of the first failure paragraph). Giving someone their intent (not the task, the intent) plus a complication is a valid thing for Mouse Guard but not legal in BW. A boring complication is the task failing as well (Page 32, flat negatives are discouraged) but regardless of how the events unfold their intent does not come to pass. For your specific question having the guard arrive before the lock is opened is totally valid because it’s not a roadblock (you’re caught red-handed trying to open a lock, what do you do?). My preference for having the task succeed is simply because I find it easier to block on intent and let task succeed. As for my specific comment about failure being the opposite of intent, that was vague and you should take my first sentence here as my real opinion on the matter.

Say Yes / Say No.
I would say that if you’re saying no with a lot of regularity while still following the rules, it’s less an issue of getting Burning Wheel and more an issue of you guys expecting different games. For example, if I’m running a gritty dark fantasy game and all my players want some gonzo high fantasy, I’m going to be saying no a lot because their intents aren’t valid. If you find yourself saying no often you should sit down and chat about the expectation of the game. In most games, things that you say no to would be Say Yes situations in a different game. As others have said though, you should only be telling people no if it’s an invalid intent. If people are trying to do valid things that you don’t expect/don’t want, it is still allowed due to it passing the validity check.

One last thing involving intent: if people are being vague on their intent you should ask them why they want to do something. Suss out how the things they want to do are in service of their beliefs, push them to work towards their goals, and make sure that the stuff that’s not pushing towards those goals you say yes to. Say Yes as a rule exists to keep the game focused and only engaging with the stuff that impacts the big picture, situation, and the character’s BITs by having the game spend zero time on those things that don’t matter.

You can use “say no” as a tool to build tension aswell (Vincent Baker) but you should try to say yes to more rolls than you’re comfortable with.