I think this is an example of exactly what I was really getting at. Rules for any individual table are decided by consensus of that table. If 51% of tables use the same rule, that rule becomes more common than any other. If a rule hits a certain level of popularity, it becomes the norm. If we take the above and replace rule with expectation, or convention, it changes nothing.
But if they are
rules, then (whether or not everyone was on board for them),
they must be applied consistently. That doesn't mean they trigger every second. But when they do, they should be used.
And no, things do change. Expectations are often not met. Conventions can be set aside at any time for nearly any reason. Rules, in order to
be "rules", must have SOMETHING to them that actually makes them normative. If they are not, in fact,
actually normative--if they are simply guidance or a gesture at something or whatever--then
they are not rules.
That's what "rules"
means. Without actual force, they are mere suggestions.
If we remove the textual aspect from this thought exercise. And we assume a game without a published rule book, but one passed down from generation to generation. If the majority of people use a popular convention for this game, does the original rule matter? At what percentage of use does the convention become the rule? If only 5% use the original rule, is that a rule or a convention? Does it matter?
If it has no published rulebook and 100% of the things as part of the game are purely conventions, it has no rules.
"Poker", to give you an example, has almost no
rules because without greater specificity you know almost nothing about it. You don't know whether it's five cards or seven cards or more or fewer. You don't know whether there are community cards or not. You don't know the scoring, etc., etc. You don't even know if the dealer is a player or not. Without greater specificity, just about the only "rules" are that that players get dealt some number of cards, and that rarer combinations of cards have greater value, but you don't even know the specific combinations.
Here we have the DMG. The DMG has a phrase. That phrase is, by my guess, the overwhelmingly most popular behavior.
Absolutely the hell not, considering we
just had a recent thread about this stuff and the majority opinion was "roll in the open."
Does it matter if it is a rule or a convention? If 51% use it, it's more popular than the alternative.
It matters, because a rule has normative force. A convention does not. "Maps are oriented with North pointing up" is a convention,
vastly more popular than any alternative. Yet nothing even remotely stops a person from publishing a map with any direction, even an ordinal direction, pointing up. Some maps even
can't be oriented that way, e.g. polar maps or ones that attempt to preserve area without preserving direction (the "orange peel" type maps).
Popularity is irrelevant to whether it has normative force. Plenty of laws are quite unpopular. That doesn't mean it's suddenly not a law anymore.
Just like laws, rules are rules because they have normative force. If someone actually breaks a rule, their behavior has to be
corrected. If a statement can be ignored or not at leisure, it has no normative force. It isn't a rule. It's a guideline, suggestion, recommendation, or piece of advice--not a rule. This applies as much to house rules as it does to anything else; a house rule is not a house
suggestion, it is in fact actually a rule that people are expected to follow.
Even DMs have rules--even in 5e, as much as it tries to position the DM as an autocrat who does whatever she wants, whenever she wants, for as long as she wants, purely because she wants to do so, for any reason or no reason at all.
At what point does it become the rule? Is it the rule when it's also the expectation? If it is the dominate expectation, let's say 80%, it seemingly becomes the starting point for discussions. At this point is it a rule or convention?
No. It's when it has actual normative force. While "expectation" (dominant or otherwise) is technically irrelevant, it is important that the rules actually be communicated to the player, which might qualify for however you define "the expectation." Something that has normative force, but which is concealed from the people upon whom that normative force applies, is not just a rule--it is coercion, or worse.
Simply put: Does it have normative force, or not? If it is in fact normative, then it is a rule. If it is not normative, if it is merely suggestive, allusive, advising, recommending, etc., then it is not a rule.
I don't see a functional difference. Do I call max HP at level one a rule because it's in the rule book or because it's the dominate way to play? If it's the latter is fudging a rule because it's the most popular? If it's the former, is fudging a rule because it's in the rule book?
Whether you choose to
call it a rule does not actually affect whether it
is a rule. People
call things by incorrect names all the time.
Fudging is when a person (generally, the DM) lies about some result or figure, generally a die roll, claiming that that result was something other than what it actually was. I say "generally, the DM" because when
players do this, it is called what it is: cheating.
Fudging cannot be a rule because, by definition, it is
lying about the results. Hence, it is (by definition) breaking the rules. I'm aware that the text of 5e has a non-normative
suggestion that DMs should lie about results if they think their false result is superior to the true one. I strenuously disagree with this suggestion, and find it both patronizing and insulting to the players subjected to its "advice."
Is it only developer intent? And if so, using the prior example, is the original rule all that matters even numerous generations after it stops being used? If no, at what point is the original rule no longer the rule, but the convention is?
When it has normative force. It is a very simple standard. As soon as something actually has normative force, it is a rule. It doesn't matter whether this normative force was acquired because a designer wrote it down, or because an old game fell out of fashion and a new one replaced it. Chess, as we play it today, is rather a different game from its High Medieval counterpart; what we call "chess" today was originally, yes, a
convention called "Mad Queens" chess. It was, in fact, a scandalous SJW game in its heyday, because women could play chess just as well as men could, and could
beat them, and (worst of all!) a woman was the
most powerful piece on the board, while a man--the king, for God's sake!!!--was the second-
weakest piece on the board.
It's really hard to decipher when something is a rule and when it's a convention outside of someone just proclaiming it. So I am really curious where that line is for you. Is it usage based? Is it developer intent? What makes a rule a rule and not a convention?
It really isn't. A rule has normative force. Non-rules do not have normative force.