Awhile ago, a very wise man gave us this, and I believe the majority of people liked/agreed with it at the time. Personally, I find it to be a very sound template to go with.
Silknor, From Zoo Mafia Page 3 wrote:As I see it there's three main avenues of bastardy:
1. The lie. This is the classic type. A PM that says you're a vanilla townie, but you're really a SK+Doctor who can self protect (but you have to send in a PM to do so each night) and dies if they use the word "the" is bastardy of the of classic sense. The first part is a plain old lie. The second part (not mentioning a lethal posting restriction) is a lie of omission. Now, it's important to note what would not be a lie of omission: creating a role where someone can privately day kill anyone who used the word "the" in a post, and they have unlimited daykills. That information obviously doesn't belong in the PM of anyone but the daykiller, so it's not a lie of omission. It might not even be bastardy, but it sure sounds like bad modding.
2. Mod intervention.
a. When obviously violating the rules. It's easiest to think about this in terms of a completely open game. If the mod has a cop listed as sane and no one cop-immune, but two scum got lynched d1 and d2 and so there's only one left so the mod changes the other scum to cop immune without telling anyone, then it's clear bastardy. It's less bastardy if they announce the rule change, probably even a justifiable form of bastardy in some circumstances, but it's still bastardy to me. Now in a closed game, it's less clear where bastardy ends. If you tell the cop they're sane and don't mention if some may be cop immune, it's easier to make the rule change without anyone knowing (except the scum you're helping).
b. In a way where it's impossible to prove the rules where violated. Eg. if the mod says they'll flip a coin (eg to determine if a 50% success rate doctor fails or tie breaking a lynch), but really they use purposeful decisions. It's clearly bastardy, regardless of it the mod intervened (made a decision based on some value instead of a random pick) to help make the game more balanced or to help one team win without regard to balance. But most would say the former type is more acceptable, even if it's still bastardy.
c. In a way that violates norms, but neither follows nor violates any rule given for the game. I can't ever remember reading a role that says the mod can't arbitrarily decide to tell random town players who the scum are outside of the stated rules and normal procedures (eg. cops, or roughly, the practice of telling guards in sins who the king is). If I give someone a role called Amy Wannabe, and tell them who all the scum are at the start, that's neither mod intervention nor bastardy (it's just very likely to be bad modding). But if I see the town is falling behind so I tell a pair of townies each who one of the scum is, that's intervention and it's bastardy (unless it's following a proscribed rule, in an open game it wouldn't be bastardy at all to have a rule that says at double LYLO, the mod shall tell a random town player the name of a random scum player, in a closed game, that rule if extant from the start would still violate #3 below and so be bastardy, though it would no longer be intervention).
d*. Non-bastard intervention. There's some classic examples of this. The oracle and inventor in contemporary usage are by definition interventionist. Unless you made the oracle results and inventions before the game started, there's no way they couldn't be. And yet I would certainly hesitate to call including an oracle or inventor bastardy, even in a closed game. Now, some inventions may be bastardy in that they break #3, or create opportunities for the breaking of 2b. or 2c. for example. And they may be strongly interventionist if, as is common, inventions are more likely to be powerful as the inventor's side becomes more likely to lose. But they're not by definition, in my view, bastardy. There's some non-classic examples of this too, including a role I've used in a previous game (*wink*, really though, there's nothing to gain by looking it up).
3. The truth you can't handle. Say the mod, in a closed game, creates a role that flaunts an unwritten rule. One that shatters expectations about what's fair, balanced, acceptable, or even mafia at it's core. A great example of this is a role I considered for Openly Bastard when it was still a closed game: One of their powers would have been the ability to read spoilers in the discussion thread for my game. Obviously switching to open lead me to drop this idea. By the way, this role is not in this game, even remotely, and it's highly unlikely I'll ever implement it, especially now that I've mentioned it to people outside some of my co-mods for that game. Strictly applying the other standards, this is not bastardy, as long as no rule is posted in the game thread (even by reference) that says players can't read spoilers. So clearly the strict standards don't capture all of the essence of bastardy, because I can't imagine very many people would say this role isn't bastardy.
No where in here of course is there reason to classify as bastard a role that meets conventional usage of the word, but not the technical mafia usage. The role I received in Asylumafia was bastard in the sense that it made me think OMGUSUBastard (ok I didn't think that, but I'd have been fairly justified in thinking it). I wasn't allowed to use the letter e. If that was done for mean-spirited reasons (which I don't suspect), it'd modding by a bastard but not bastard modding.
Ok so as you can see, I excessively enjoy discussing bastard modding, even though I so rarely practice it myself. Now I think there was a question which prompted my explanation, so lets take a stab at answering what I think you actually want to know.